THESAURUS
mum
anaudic, aphasic, aphonic, breathless, brief, brusque, close, close-tongued, closemouthed, concise, curt, dumb, dumbfounded, dumbstricken, dumbstruck, economical of words, inarticulate, indisposed to talk, laconic, ma, mam, mama, mammy, mater, mom, mommy, mummy, mute, old woman, quiet, short, silent, snug, sparing of words, speechless, stricken dumb, taciturn, terse, tight-lipped, tongue-tied, tongueless, unloquacious, untalkative, voiceless, word-bound, wordless
ROGET THESAURUS
mum
Aphony
N
aphony, aphonia, dumbness, obmutescence, absence of voice, want of voice, dysphony, cacoepy, silence, raucity, harsh voice &c, unmusical voice, falsetto, childish treble mute, dummy, aphonous, dumb, mute, deafmute, deaf and dumb,
mum, tongue-tied, breathless, tongueless, voiceless, speechless, wordless, mute as a fish, mute as a stockfish, mute as a mackerel, silent, muzzled, inarticulate, inaudible, croaking, raucous, hoarse, husky, dry, hollow, sepulchral, hoarse as a raven, rough, with bated breath, with the finger on the lips, sotto voce, in a low tone, in a cracked voice, in a broken voice, vox faucibus haesit.
Taciturnity
N
taciturnity, silence, muteness, obmutescence, taciturnity, pauciloquy, costiveness, curtness, reserve, reticence, man of few words, silent, mute,
mum, silent as a post, silent as a stone, silent as the grave, dumb, unconversable, taciturn, sparing of words, closetongued, costive, inconversable, curt, reserved, reticent, Int, shush!, tush!, silence!,
mum!, hush!, chut!, hist!, tut!, chup!,
mum's the word, keep your mouth shut!, cave quid dicis quando et cui, volto sciolto i pensieri stretti.