What is the meaning of fatal?

adjective

• Bringing death.
• Having momentous consequences; of decisive importance.
  • usage: "that fateful meeting of the U. N. When... It declared war on North Korea- Saturday Rev; "the fatal day of the election finally arrived"
  • synonyms: fateful
• Of events. ( having extremely unfortunate or dire consequences; bringing ruin)
  • usage: "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"
  • synonyms: black, calamitous, disastrous, fateful
• Controlled or decreed by fate; predetermined.
  • usage: "a fatal series of events"
  • synonyms: fateful