Meaning & use
mum's the word
Used to tell someone to keep a piece of information secret and say nothing about it.
See it in a sentence
We're planning a surprise party, so mum's the word until Saturday.
The lawyer reminded her client that mum's the word regarding the settlement.
A note on using this word
In this idiom, "mum" is an old word meaning silent, unrelated to "mum" meaning mother.
Words with a similar meaning
keep quiethush-hush
Choose a synonym to suit the sentence. Meanings can overlap without being identical.
Make it your own
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