calamitous

Borrowed from French calamiteux (“calamitous”) (see French -eux, English -ous), from Latin calamitōsus (“destructive, disastrous, ruinous, calamitous”), a contraction of calamitātōsus, from calamitāt- + -ōsus (suffix meaning ‘full of; prone to’ forming adjectives from nouns); calamitāt- is the oblique stem of calamitās (“disaster, misfortune, calamity; damage, harm; loss”), from calamis (“damaged”) (ultimately from Proto-Indo-European kelh₂- (“to beat; to break”)) + -tās (suffix forming abstract nouns denoting a condition or state). By surface analysis, calamity + -ous.