mum's the word

INFORMAL
This page is about the conversational phrase mum's the word

Meaning

You can say this to let someone know that what you've told them is a secret, and they mustn't tell anyone.

For example

  • "This is top secret - mum's the word, OK?"
    "My lips are sealed, I swear."

  • "If I tell you, mum's the word."
    "I won't tell anyone else, I promise."

Note:
Can also be used to mean "I promise not to tell anyone", as in: "Don't tell anyone, OK?" "Sure. Mum's the word."

Quick Quiz

If someone says "Mum's the word" while telling you something, you should

a. only tell a few people

b. only tell your mum

c. tell no-one at all

Contributor: Matt Errey