Word Originadjective late Middle English: imitative of a sound made with closed lips.Idiomsadjectivejump to other results
BrE BrE//mʌm//; NAmE NAmE//mʌm//
(informal) to say nothing about something; to stay quiet He kept mum about what he'd seen.
keep mumjump to other results
(informal) used to tell somebody to say nothing about something and keep it secret
mum’s the word!jump to other results