Origin: Latin suffix -ous
Calamitous has 2 different meanings across 1 category:
(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"
"it is fatal to enter any war without the will to win it"
"a fateful error"
Concerning or involving calamity, disastrous.