Synonyms and related words :
aloof, autistic, bashful, canny, careful, cautious, circumspect, close, close-lipped, close-tongued, closemouthed, dark, deliberate, discreet, disinclined to communicate, dissociable, distant, evasive, gingerly, guarded, heedful, hesitant, incompatible, insociable, judicious, leaving out nothing, meaningless, mindful, mopey, mopish, morose, noncommittal, nongregarious, offish, on guard, overlooking no possibility, pawky, politic, prudent, regardful, reserved, reticent, safe, secret, secretive, self-contained, self-sufficient, shifty, slow to act, snug, socially incompatible, standoffish, sullen, taciturn, tentative, thorough, tight-lipped, unadventurous, unapproachable, unbending, unclubbable, uncompanionable, uncongenial, unconversable, undaring, unenterprising, unfriendly, ungenial, unprecipitate, unsociable, unsocial, withdrawn