List of constrained synonyms and constrained related words.
Olympian, aloof, arrested, backward, bashful, blank, bridled, chastened, chilled, chilly, cold, controlled, cool, curbed, detached, discreet, distant, expressionless, forbidding, frigid, frosty, guarded, hushed, icy, impassive, impersonal, in check, in control, in hand, in leading strings, in remission, inaccessible, incommunicable, inhibited, introverted, limited, modest, noncommittal, offish, on leash, pent-up, quelled, quiet, remote, removed, repressed, reserved, restrained, retarded, reticent, retiring, shrinking, slowed down, softened, stable, standoff, standoffish, subdued, suppressed, tempered, unaffable, unapproachable, uncongenial, undemonstrative, under control, under discipline, under restraint, unexpansive, ungenial, withdrawn