Synonyms of unintentional

2 Syllables
chanced, random, aimless, will-less, casual, re-flex, chancing, chancer, unthought, chance
3 Syllables
spontaneous, unbidden, erratic, haphazard, unplanned, fortuitous, unwitting, unthinking, unconscious, unwilled
4 Syllables
unintended, purposeless, aleatory, inadvertent, undesigned, undevised, reflexive, accidental, unexpected, unforeseen, coincidental
5 Syllables
unpremediated, extemporaneous, uncalculated, irreflective, involuntary, autogenetic
6 Syllables
unpremeditated, undeliberate