fateful in WordNet English dictionary

1. (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"
   black  calamitous  disastrous  fatal  fateful 
   
2. 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"
   fateful  fatal 
   
3. controlled or decreed by fate; predetermined
   "a fatal series of events"
   fatal  fateful 
   
4. ominously prophetic
   fateful  foreboding  portentous