adj.

1. having momentous consequences; of decisive importance;
   fatal
   
   • that fateful meeting of the U.N. when...it declared war on North Korea"- Saturday Rev; "the fatal day of the election finally arrived
2. ominously prophetic;
   foreboding(a), portentous
3. (of events) having extremely unfortunate or dire consequences; bringing ruin;
   black, calamitous, disastrous, fatal
   
   • 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
4. controlled or decreed by fate; predetermined;
   fatal
   
   • a fatal series of events