adjective
silent, unsociable; constrained
Synonyms: aloof, backward, bashful, cautious, ceremonious, close, close-mouthed, cold, collected, composed, conventional, cool, demure, diffident, distant, eremitic, formal, frigid, gentle, icy, mild, misanthropic, modest, noncommittal, offish, peaceful, placid, prim, quiet, reclusive, restrained, reticent, retiring, secretive, sedate, self-contained, serene, shy, soft-spoken, solitary, standoffish, taciturn, unapproachable, uncommunicative, uncompanionable, undemonstrative, unresponsive, withdrawn
Antonyms: extroverted, friendly, outgoing, sociable
adjective
held for future use
Synonyms: appropriated, arrogated, booked, claimed, engaged, kept, laid away, limited, preempted, private, qualified, restricted, retained, roped off, set apart, set aside, spoken for, taken
Antonyms: given, offered, unreserved