keep it under your hat
Meaning
Keep something secret; don’t tell anyone about it.
Origin
From the idea of hiding something beneath a hat so others can’t see it; recorded in English from the 19th century as a metaphor for keeping information concealed.
Notes
Casual, friendly way to ask someone to keep a secret, often used as an imperative (“Keep it under your hat”).
Examples
-
Keep it under your hat for now—we're not announcing the merger until next week.
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I’ll tell you what happened, but you have to keep it under your hat.
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The boss asked everyone to keep the new policy under their hat until the meeting.
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If you can keep it under your hat, I’ll share the surprise party details.
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She kept her promotion under her hat so she wouldn’t make anyone feel awkward.
Grammar & Usage Notes
Usually used with a pronoun object (“keep it under your hat”). Can take a noun (“keep the news under your hat”). Tense can change (kept/keeping), but wording is fairly fixed.
Synonyms
- keep it quiet
- keep it to yourself
- keep it secret
- keep it confidential
- hush-hush
Antonyms
- spill the beans
- let the cat out of the bag
- blab
- divulge