mum2
adj.
(
in phr. keep mum)
informal remain silent so as not to reveal a secret.
Phrase
- mum's the word
do not reveal a secret.
Etymology
ME: imitative of a sound made with closed lips.
mum3
v.
(mums, mumming, mummed)
act in a mummers' play.
Etymology
ME: cf. mum2 and Mid. Low Ger. mummen.