Roget's Thesaurus of English Words and Phrases by Peter Mark Roget

pauciloquy†, costiveness†, curtness; reserve, reticence &c (concealment) 528. man of few words. V. be silent &c adj.; keep silence, keep mum; hold one's tongue, hold one's peace, hold one's jaw; not speak. &c 582; say nothing, keep one's counsel; seal the lips, close the lips, button the lips, zipper the lips, put a padlock on the lips, put a padlock on the mouth; put a bridle on one's tongue; bite one's tongue, keep one's tongue between one's teeth; make no sign, not let a word escape one; keep a secret &c 528; not have a word to say; hush up, hush, lay the finger on the lips, place the finger on the lips; render mute &c 581. stick in one's throat. Adj. silent, mute, mum; silent as a post, silent as a stone, silent as the grave &c (still) 403; dumb &c 581; unconversable†. taciturn, sparing of words; closetongued; costive†, inconversable†, curt; reserved; reticent &c (concealing) 528. Int. shush!, tush!, silence!, mum!, hush!, chut!†, hist!, tut!, chup!†, mum's the word; keep your mouth shut! [Vulg.]. Phr. cave quid dicis quando et cui [Lat.]; volto sciolto i pensieri stretti [It].