fatal (Adjective) — Bringing death.
fatal (Adjective) — Having momentous consequences; of decisive importance. ex. "the fatal day of the election finally arrived"
fatal (Adjective) — (of events) having extremely unfortunate or dire consequences; bringing ruin. ex. "such doctrines, if true, would be absolutely fatal to my theory" ex. "it is fatal to enter any war without the will to win it"
fatal (Adjective) — Controlled or decreed by fate; predetermined. ex. "a fatal series of events"