adjective

mum

silent, quiet

He kept mum about his plans.

He kept mum about his plans.

Mum's the word.

Mum's the word.

to keep mum ((about sth.)) to remain silent about (sth.) He kept mum about his plans.

Mum's the word. (idiom) Keep this a secret. Mum's the word.

Synonyms: silent, quiet, tight-lipped, taciturn; Antonyms: talkative, chatty, loquacious

Likely from the 'mmm' sound made with closed lips, suggesting an inability or unwillingness to speak.

The word 'mum' sounds like the sound you make when your mouth is closed. That's why it means to be silent.

This page is designed for learning support. Please use it as a learning reference, not as a formal reference.