Synonyms of mum's the word in English:

mum's the word

See definition of mum's the word



say nothing, keep quiet, don't breathe a word, don't tell a soul, don't give the game away, keep it secret, keep it to yourself, keep it under your hat, play dumb
Scottish play the daft baddie, play the daft lassie
informal don't let on, keep shtum, don't let the cat out of the bag