means A prediction or foretelling of what is to come, especially one delivered as divinely inspired or carrying an air of certainty.

from From Greek 'prophēteia,' the office of a 'prophētēs' — literally one who speaks (phēmi, 'to speak') 'before' or 'on behalf of' (pro-) the gods. It traveled through Latin 'prophetia' and Old French before settling into English. Note the spelling split English later imposed: 'prophecy' the noun (the thing foretold) versus 'prophesy' the verb (the act of foretelling) — same root, divided by a single vowel doing quiet grammatical work.