mum

/məm/

/məm/

Other forms: mums; mumming

Someone who's mum has nothing to say, especially on a particular subject. If you agree to keep someone's secret, you could tell them, "Mum's the word!"

A shy child who's new at school might stay mum all day, and even your most talkative friend might remain mum on controversial topics like religion and politics. In many parts of the world, mum is also a nickname for your mother — and it's also a nickname for the flower called a chrysanthemum. The "quiet" meaning of mum comes from Old English, inspired by the "mmm" sound you make when your lips are closed.

Definitions of mum

1. adjective

   failing to speak or communicate etc when expected to
   synonyms: silent

   incommunicative, uncommunicative

   not inclined to talk or give information or express opinions
2. noun

   secrecy
   “mum's the word”

   type of:

   secrecy, secretiveness, silence

   the trait of keeping things secret
3. noun

   informal terms for a mother
   synonyms: ma, mama, mamma, mammy, mom, momma, mommy, mummy

   type of:

   female parent, mother

   a woman who has given birth to a child (also used as a term of address to your mother)
4. noun

   of China
   synonyms: Chrysanthemum morifolium, Dendranthema grandifloruom, florist's chrysanthemum, florists' chrysanthemum

   type of:

   chrysanthemum

   any of numerous perennial Old World herbs having showy brightly colored flower heads of the genera Chrysanthemum, Argyranthemum, Dendranthema, Tanacetum; widely cultivated