1640s, noun of action from infatuate (q.v.), or else from French infatuation or directly from Late Latin infatuationem (nominative infatuatio), from past participle stem of Latin infatuare "make a fool of."
infantryman
infarct
infarction
infatigable
infatuate
infatuation
infeasibility
infeasible
infect
infection
infectious