Definition of calamitous
(of events) having extremely unfortunate
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"