Synonyms for Unintentional (same or very similar meaning)
WordNet sense 1 (without deliberate intent):
unwilled
WordNet sense 2 (not disposed or inclined toward):
unwilling
WordNet sense 3 (not done or made or performed with purpose or intent):
undesigned
WordNet sense 4 (not intentional):
unplanned, unwitting
WordNet sense 5 (not deliberate):
unintended
From the ODE community, based on WordNet
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