mum

[1]	florist's chrysanthemum , florists' chrysanthemum , Dendranthema grandifloruom , Chrysanthemum morifolium
[2]	ma , Mum's the word , Don't tell a soul , mama , Keep silent , mamma , mom , Keep secret , Keep quiet , momma , mommy , Keep (something) to oneself , Keep (something) under one's hat , mammy , mummy , Say nothing , Tell no-one , Play dumb

adj.

[1]	silent , mute , close-mouthed , quiet , tight-lipped
[2]	silent