Synonyms and related words :
automatic, blind, casual, causeless, chance, compulsive, conditioned, forced, gut, haphazard, ill-advised, ill-considered, ill-devised, impulsive, inadvertent, indeliberate, instinctive, involuntary, mechanical, purposeless, random, reflex, reflexive, snap, spontaneous, unadvised, unanticipated, uncalculated, unconscious, unconsidered, undeliberate, undeliberated, undesigned, undevised, unexpected, unforeseen, unguarded, unguided, unintended, unlooked-for, unmeant, unmeditated, unplanned, unpremeditated, unprompted, unpurposed, unstudied, unthinking, unthought, unthought-of, unwilled, unwilling, unwitting