fateful

Adjective

• controlled or decreed by fate; predetermined
  • a fatal series of events
    

• (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
    

• ominously prophetic

• 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
    

Related words

• Synonyms: 
  fatal , black , calamitous , disastrous , foreboding(a) , portentous