tempestuous

From Late Middle English tempestious, tempestous, tempestuous (“stormy, turbulent, tempestuous”), from Anglo-Norman tempestous, and Old French tempesteus, tempestos, tempestous, tempestuose (modern French tempétueux), and directly from its etymon Latin tempestuōsus (“stormy, turbulent, tempestuous; impetuous”), from tempestās, tempestūs (“point or period of time; season; weather, specifically bad weather; storm, tempest”) (from tempus (“period of time; (rare) weather”), possibly from Proto-Indo-European *temh₁- (“to cut”) or *ten- (“to extend, stretch”)) + -ōsus (suffix meaning ‘full of; overly; prone to’ forming adjectives from nouns). The English word is equivalent to tempest +‎ -uous (a variant of -ous (suffix forming adjectives from nouns, denoting the presence of a quality, typically in abundance)).