fateful, fatal -- (having momentous consequences; of decisive importance; "that fateful meeting of the U.N. when...it declared war on North Korea"- Saturday Rev; "the fatal day of the election finally arrived")
black, calamitous, disastrous, fatal, fateful -- ((of events) having extremely unfortunate or dire consequences; bringing ruin; "the stock market crashed on Black Friday"; "a calamitous defeat"; "the battle was a disastrous end to a disastrous campaign"; "such doctrines, if true, would be absolutely fatal to my theory"- Charles Darwin; "it is fatal to enter any war without the will to win it"- Douglas MacArthur; "a fateful error")
fatal, fateful -- (controlled or decreed by fate; predetermined; "a fatal series of events")