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Idioms are fun phrases where the words together mean something totally different from what they say one by one. People use them to make talking and writing more colorful, exciting, and full of life. Today, you are going to learn a bunch of helpful idioms that all have to do with keeping secrets and holding information close.
In this lesson, we’ll look at idioms for keeping secrets that mean staying quiet, guarding private news, and not telling anyone. Let’s get started and explore some of these helpful expressions.
Idioms for Keeping Secrets
1. Keep your lips sealed
Meaning: To promise completely not to speak a word about a secret.
For Example: He promised to keep his lips sealed about the surprise party. / Make sure you keep your lips sealed when I tell you this fun story.
Other Ways to Say: Stay quiet / Keep secret
2. Mum is the word
Meaning: A phrase used to tell someone to remain silent and not share a secret.
For Example: I will tell you where the hidden toy is, but mum is the word. / Remember that mum is the word about our club plans.
Other Ways to Say: Stay silent / Do not tell
3. Take it to the grave
Meaning: To keep a secret so safely that you will never tell anyone as long as you live.
For Example: He swore he would take it to the grave and never reveal the hiding spot. / This information is private, so take it to the grave.
Other Ways to Say: Keep forever / Guard secret
4. Spill the beans
Meaning: To accidentally or purposely tell a secret to someone who isn’t supposed to know.
For Example: He accidentally spilled the beans about the surprise vacation. / Try not to spill the beans before the party starts.
Other Ways to Say: Reveal the secret / Let slip
5. Cat got your tongue
Meaning: Asking why someone is being unusually quiet and keeping a secret.
For Example: You look very quiet today, what is the matter, cat got your tongue? / He smiled and stayed silent as if the cat got his tongue.
Other Ways to Say: Staying quiet / Speechless
6. Off the record
Meaning: Information shared privately that should not be repeated publicly.
For Example: What I am about to tell you about the game strategy is strictly off the record. / He whispered a quick detail that was off the record.
Other Ways to Say: Private information / Confidential
7. My lips are sealed
Meaning: A promise stating that your mouth will stay closed and you won’t talk.
For Example: Don’t worry about me telling anyone because my lips are sealed. / She crossed her heart and said my lips are sealed.
Other Ways to Say: I won’t tell / Staying quiet
8. Let the cat out of the bag
Meaning: To reveal a secret by mistake before it is time.
For Example: She let the cat out of the bag about the surprise puppy. / Be careful not to let the cat out of the bag during dinner.
Other Ways to Say: Reveal secret / Slip up
9. Keep something under wraps
Meaning: To keep a plan, project, or piece of news hidden from others.
For Example: We decided to keep our treehouse design under wraps until it was finished. / The art teacher kept the contest winners under wraps.
Other Ways to Say: Hide plan / Keep secret
10. Bury a secret
Meaning: To hide information so deeply that nobody will ever discover it.
For Example: He decided to bury a secret about where he hid the extra crayons. / Some mysteries are better left to bury a secret forever.
Other Ways to Say: Hide information / Conceal
11. Play your cards close to your chest
Meaning: To keep your plans and secrets hidden from other people.
For Example: During the board game, he liked to play his cards close to his chest. / The coach played his cards close to his chest about the game lineup.
Other Ways to Say: Be secretive / Hide plans
12. Lock it away
Meaning: To store information in your mind securely without sharing it.
For Example: Hear this news and lock it away safely in your memory. / He promised to lock it away and never repeat it.
Other Ways to Say: Hide away / Keep safe
13. Skeleton in the closet
Meaning: A shameful or embarrassing private secret from the past.
For Example: Everyone has some minor skeleton in the closet they prefer not to discuss. / He worried his old art project failure was a skeleton in the closet.
Other Ways to Say: Hidden secret / Past mistake
14. Keep a lid on it
Meaning: To keep information or excitement quiet and hidden.
For Example: The principal asked us to keep a lid on the school assembly news. / Try to keep a lid on your laughter so you don’t spoil the joke.
Other Ways to Say: Keep quiet / Hide news
15. Keep it dark Meaning: To ensure a piece of news remains a hidden secret.
Meaning: To ensure a piece of news remains a hidden secret.
For Example: We found a great hiding spot for the gift, so let’s keep it dark. / He told his friend the news and asked him to keep it dark.
Other Ways to Say: Keep secret / Hide it
16. Keep your own counsel Meaning: To keep your thoughts and plans entirely to yourself.
Meaning: To keep your thoughts and plans entirely to yourself.
For Example: When planning the surprise, it is best to keep your own counsel. / He never shared his ideas and preferred to keep his own counsel.
Other Ways to Say: Be private / Keep quiet
17. Safe as houses Meaning: A secret or hiding place that is completely secure.
Meaning: A secret or hiding place that is completely secure.
For Example: You can trust me with your diary because your secret is safe as houses. / Our hiding spot in the attic is safe as houses.
Other Ways to Say: Completely secure / Very safe
18. Not a word Meaning: A short command telling someone to remain entirely silent.
Meaning: A short command telling someone to remain entirely silent.
For Example: I will share the riddle answer, but not a word to anyone else. / He nodded at his friend, meaning not a word.
Other Ways to Say: Stay silent / Quiet
19. Hold your tongue Meaning: To stop yourself from speaking or sharing a secret.
Meaning: To stop yourself from speaking or sharing a secret.
For Example: She had to hold her tongue so she wouldn’t ruin the surprise ending. / Remember to hold your tongue during the magic trick.
Other Ways to Say: Stay quiet / Don’t speak
20. Bite your tongue Meaning: Forcing yourself not to say something revealing.
Meaning: Forforcing yourself not to say something revealing.
For Example: He had to bite his tongue to avoid giving away the game answer. / Biting your tongue is important when someone is telling a surprise.
Other Ways to Say: Stay silent / Stop talking
21. Keep things under cover Meaning: Concealing activities or information from public view.
Meaning: Concealing activities or information from public view.
For Example: The club members worked hard to keep things under cover for the fair. / Keep things under cover until the big reveal.
Other Ways to Say: Hide work / Conceal actions
22. Silent as the grave Meaning: Absolute and total quietness regarding a secret.
Meaning: Absolute and total quietness regarding a secret.
For Example: When asked about the missing cookies, he was silent as the grave. / Promise to remain silent as the grave about this plan.
Other Ways to Say: Completely quiet / Mute
23. Silent as a statue Meaning: Standing or sitting without making a sound or motion.
Meaning: Standing or sitting without making a sound or motion.
For Example: During hide and seek, she stayed silent as a statue. / He remained silent as a statue while listening to the secret.
Other Ways to Say: Very quiet / Motionless
24. Keep dark Meaning: Maintaining secrecy around a plan or piece of news.
Meaning: Maintaining secrecy around a plan or piece of news.
For Example: We wanted to surprise mom, so we agreed to keep dark about breakfast. / Keep dark about where we hid the supplies.
Other Ways to Say: Keep secret / Hide information
25. Hush-hush Meaning: Extremely secret, confidential, and quiet.
Meaning: Extremely secret, confidential, and quiet.
For Example: The mission to plan the party was very hush-hush. / They whispered in the corner about hush-hush project details.
Other Ways to Say: Very secret / Confidential
26. Under wraps Meaning: Concealed safely so nobody discovers the plan early.
Meaning: Concealed safely so nobody discovers the plan early.
For Example: The new comic book release was kept strictly under wraps. / Keep your art project under wraps until art class.
Other Ways to Say: Hidden / Secret
27. Confidential Meaning: Private information meant only for trusted ears.
Meaning: Private information meant only for trusted ears.
For Example: The letter marked confidential contained the spelling bee words. / Treat this information as confidential between us.
Other Ways to Say: Private / Secret
28. Behind closed doors Meaning: Private meetings or secrets kept away from public eyes.
Meaning: Private meetings or secrets kept away from public eyes.
For Example: The club discussed the special award behind closed doors. / Important decisions were made behind closed doors.
Other Ways to Say: Private discussion / Secret meeting
29. Keep under your hat Meaning: To keep a thought or secret strictly to yourself.
Meaning: To keep a thought or secret strictly to yourself.
For Example: I will tell you who won the contest, but keep it under your hat. / He promised to keep the news under his hat.
Other Ways to Say: Keep secret / Don’t tell
30. Cloak and dagger Meaning: Involving mystery, espionage, and secret activities.
Meaning: Involving mystery, espionage, and secret activities.
For Example: Passing notes in class felt like a cloak and dagger operation. / The mystery book was full of cloak and dagger excitement.
Other Ways to Say: Mysterious / Secretive
31. Playing it close to the vest Meaning: Hiding your intentions and secrets carefully.
Meaning: Hiding your intentions and secrets carefully.
For Example: He was playing it close to the vest about his puzzle strategy. / Good leaders play it close to the vest during competitions.
Other Ways to Say: Be cautious / Hide plans
32. Harbor a secret Meaning: To hold and protect private information in your mind.
Meaning: To hold and protect private information in your mind.
For Example: She spent the whole week harboring a secret about the puppy. / It is tough harboring a secret from your best friend.
Other Ways to Say: Keep information / Hold secret
33. Guard a secret Meaning: To protect private knowledge from being discovered.
Meaning: To protect private knowledge from being discovered.
For Example: A good detective knows how to guard a secret carefully. / Guard this password and never share it.
Other Ways to Say: Protect information / Keep safe
34. Sit on information Meaning: To delay sharing a secret or piece of news purposely.
Meaning: To delay sharing a secret or piece of news purposely.
For Example: He decided to sit on information about the test until morning. / Why are you sitting on information that helps the team?
Other Ways to Say: Withhold news / Delay telling
35. Keep a tight rein on your tongue Meaning: Controlling what you say so you don’t reveal secrets.
Meaning: Controlling what you say so you don’t reveal secrets.
For Example: You must keep a tight rein on your tongue during the surprise party. / Keeping a tight rein on your tongue prevents accidental spoilers.
Other Ways to Say: Watch words / Stay quiet
36. Button your lip Meaning: A casual instruction telling someone to stop talking.
Meaning: A casual instruction telling someone to stop talking.
For Example: He told his brother to button his lip about the hidden presents. / Button your lip so we don’t ruin the trick.
Other Ways to Say: Be quiet / Stop talking
37. Zip your lip Meaning: A playful way of telling someone to close their mouth and be quiet.
Meaning: A playful way of telling someone to close their mouth and be quiet.
For Example: Zip your lip and let me tell you the secret clubhouse rules. / The children smiled and made a zipping motion over their mouths to zip their lips.
Other Ways to Say: Be silent / Stop speaking
38. Cork it Meaning: A slang expression meaning to stop talking immediately.
Meaning: A slang expression meaning to stop talking immediately.
For Example: He whispered to his friend to cork it during the magic show. / Cork it so everyone can hear the secret announcement.
Other Ways to Say: Be quiet / Hush
39. Keep quiet Meaning: Remaining silent to protect private information.
Meaning: Remaining silent to protect private information.
For Example: Promise to keep quiet while we set up the decorations. / It is best to keep quiet about the game score.
Other Ways to Say: Stay silent / Hush
40. Keep mum Meaning: Remaining completely silent and refusing to speak.
Meaning: Remaining completely silent and refusing to speak.
For Example: When questioned by the teacher, he decided to keep mum. / She promised to keep mum about the missing puzzle piece.
Other Ways to Say: Stay quiet / Remain silent
41. Not a peep Meaning: Demanding that zero sounds or words be spoken.
Meaning: Demanding that zero sounds or words be spoken.
For Example: I want to hear not a peep from anyone while the test is active. / He whispered not a peep about the surprise gift.
Other Ways to Say: Absolute silence / No talking
42. Lock your lips Meaning: Closing your mouth tightly to symbolize secrecy.
Meaning: Closing your mouth tightly to symbolize secrecy.
For Example: Lock your lips and throw away the imaginary key. / She smiled, locked her lips, and nodded at the secret.
Other Ways to Say: Seal lips / Stay quiet
43. Sworn to secrecy Meaning: Having taken a formal promise to keep a secret.
Meaning: Having taken a formal promise to keep a secret.
For Example: All club members were sworn to secrecy about the clubhouse password. / He was sworn to secrecy before entering the room.
Other Ways to Say: Promised silence / Bound by oath
44. Bound by oath Meaning: Legally or morally required to keep information secret.
Meaning: Legally or morally required to keep information secret.
For Example: The guards were bound by oath never to reveal the castle map. / Being sworn in meant he was bound by oath.
Other Ways to Say: Sworn to secrecy / Obligated
45. Keep a poker face Meaning: Maintaining a blank expression so nobody guesses your secret.
Meaning: Maintaining a blank expression so nobody guesses your secret.
For Example: He tried to keep a poker face when his friends guessed his card. / Keep a poker face during the game so they don’t know your hand.
Other Ways to Say: Blank expression / Hide emotions
46. Hide in plain sight Meaning: Concealing a secret by keeping it visible to everyone.
Meaning: Concealing a secret by keeping it visible to everyone.
For Example: The hidden note was placed on the bulletin board to hide in plain sight. / Good spies know how to hide in plain sight.
Other Ways to Say: Conceal openly / Blend in
47. Sweep under the rug Meaning: Trying to hide an embarrassing secret or problem.
Meaning: Trying to hide an embarrassing secret or problem.
For Example: Don’t try to sweep your messy mistake under the rug; fix it. / They tried to sweep the broken vase under the rug.
Other Ways to Say: Hide trouble / Conceal error
48. Keep dark secret Meaning: Maintaining a deeply hidden and private piece of news.
Meaning: Maintaining a deeply hidden and private piece of news.
For Example: He guarded a keep dark secret about where he hid the key. / Some stories remain a keep dark secret for years.
Other Ways to Say: Hidden truth / Private mystery
49. Keep under lock and key Meaning: Storing secret items or documents securely locked away.
Meaning: Storing secret items or documents securely locked away.
For Example: The diary with all her secrets was kept under lock and key. / Keep the test papers under lock and key.
Other Ways to Say: Securely locked / Guarded safely
50. Keep your mouth shut Meaning: A direct command to avoid speaking about a secret.
Meaning: A direct command to avoid speaking about a secret.
For Example: You need to keep your mouth shut if you want the surprise to work. / He promised to keep his mouth shut about the prank.
Other Ways to Say: Stay quiet / Don’t talk
51. Bite your tongue secret style Meaning: Forcing yourself to stay silent when asked a direct question.
Meaning: Forforcing yourself to stay silent when asked a direct question.
For Example: When asked about the gift, he had to bite your tongue secret style. / She practiced biting her tongue secret style before guests arrived.
Other Ways to Say: Stay quiet / Force silence
52. Play dumb Meaning: Pretending you know nothing about a secret or event.
Meaning: Pretending you know nothing about a secret or event.
For Example: When mom asked who ate the cookie, he decided to play dumb. / Just play dumb if anyone asks about the surprise party.
Other Ways to Say: Pretend ignorance / Act innocent
53. Act innocent Meaning: Behaving as if you are unaware of any secret plans.
Meaning: Behaving as if you are unaware of any secret plans.
For Example: Try to act innocent when dad walks into the decorated room. / She tried to act innocent while holding the wrapped gift.
Other Ways to Say: Pretend unaware / Play dumb
54. Keep quiet as a mouse Meaning: Moving and speaking with total silence.
Meaning: Moving and speaking with total silence.
For Example: Walk down the hallway and keep quiet as a mouse during nap time. / The puppy stayed quiet as a mouse under the bed.
Other Ways to Say: Very quiet / Silent
55. Keep a secret Meaning: Protecting private information from being shared with others.
Meaning: Protecting private information from being shared with others.
For Example: Can you promise to keep a secret if I tell you my wish? / Learning to keep a secret is an important part of growing up.
Other Ways to Say: Guard information / Protect privacy
56. Keep out of sight Meaning: Staying hidden so nobody discovers your secret location.
Meaning: Staying hidden so nobody discovers your secret location.
For Example: Stay behind the couch and keep out of sight until we shout surprise. / The cat found a box to keep out of sight.
Other Ways to Say: Hide / Remain unseen
57. Keep behind closed doors Meaning: Ensuring discussions stay strictly private and hidden.
Meaning: Ensuring discussions stay strictly private and hidden.
For Example: We need to keep our meeting behind closed doors. / The club elections happened behind closed doors.
Other Ways to Say: Private meeting / Secret talk
58. Keep undercover Meaning: Operating secretly without letting anyone know your identity.
Meaning: Operating secretly without letting anyone know your identity.
For Example: The detective had to keep undercover while investigating the mystery. / Playing spy games involves trying to keep undercover.
Other Ways to Say: Operate secretly / Hide identity
59. Keep confidential Meaning: Marking and treating information as strictly private.
Meaning: Marking and treating information as strictly private.
For Example: Please keep confidential any details about the school play. / The teacher asked us to keep confidential the quiz answers.
Other Ways to Say: Keep private / Protect secret
60. Pure secrecy Meaning: Total and absolute dedication to keeping information hidden.
Meaning: Total and absolute dedication to keeping information hidden.
For Example: Planning the anniversary party required a level of pure secrecy. / The clubhouse operated under rules of pure secrecy.
Other Ways to Say: Absolute privacy / Total discretion
Exercise to Practice
- He promised to keep his lips ________ about the surprise party.
- I will tell you where the hidden toy is, but mum is the ________.
- He accidentally spilled the ________ about the surprise vacation.
- You look very quiet today, what is the matter, cat got your ________?
- Don’t worry about me telling anyone because my lips are ________.
- She let the cat out of the ________ about the surprise puppy.
- We decided to keep our treehouse design under ________ until it was finished.
- During the board game, he liked to play his cards close to his ________.
- When asked about the missing cookies, he was silent as the ________.
- He told his brother to button his ________ about the hidden presents.
- Promise to keep quiet while we set up the ________.
- When questioned by the teacher, he decided to keep ________.
- All club members were sworn to ________ about the clubhouse password.
- When mom asked who ate the cookie, he decided to play ________.
- Can you promise to keep a ________ if I tell you my wish?
Answer Key
- sealed
- word
- beans
- tongue
- sealed
- bag
- wraps
- chest
- grave
- lip
- decorations
- mum
- secrecy
- dumb
- secret
Conclusion
Learning idioms for keeping secrets helps you understand stories, character loyalty, and everyday privacy much better. When you know what these colorful phrases mean, you can trust friends and guard confidential information like a true professional.
Try using a few of these expressions the next time you plan a surprise for someone special. Practicing discretion and loyalty is a great way to build strong friendships and make your communication sound awesome.
