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uncompanionable uncongenial unconversable undaring unenterprising unfriendly ungenial unprecipitate unsociable unsocial withdrawn