"speak by divine inspiration, foretell future events," mid-14c., prophecein, prophesein, from Old French profeciier, prophecier (13c.), from prophecie (see prophecy). The noun and verb spellings were not fully differentiated until 18c. Related: Prophesied; prophesying. Other verb forms in Middle English were prophetise (mid-14c., from Old French profetisier and Latin prophetizare), prophet (mid-15c.).