Synonyms and related words :
automatic, casual, gut, ill-advised, ill-considered, ill-devised, inadvertent, indeliberate, involuntary, reflex, reflexive, snap, spontaneous, unadvised, uncalculated, unconscious, unconsidered, undeliberate, undeliberated, undevised, unguarded, unguided, unintended, unintentional, unmeant, unmeditated, unplanned, unpremeditated, unprompted, unpurposed, unstudied, unthinking, unthought, unthought-of, unwilled, unwitting