closemouthed

CIDE DICTIONARY

closemouthed, a. 

 Cautious in speaking; secret; wary; uncommunicative.  [1913 Webster]

THESAURUS

closemouthed

brief, brusque, close, close-lipped, close-tongued, concise, curt, dark, discreet, dumb, economical of words, evasive, indisposed to talk, laconic, mum, mute, quiet, reserved, reticent, secret, secretive, shifty, short, silent, snug, sparing of words, speechless, taciturn, terse, tight-lipped, tongue-tied, uncommunicative, unloquacious, untalkative, word-bound, wordless