vaporous

Etymology

Came into English via Middle English vaporous, from Late Latin vapōrōsus (“full of steam”), from Latin vapor (“exhalation; smoke; steam, vapour”), possibly related to Proto-Indo-European *kwep- (“to boil; to smoke, steam; aroma; strong odour”), plus -ōsus (a suffix meaning ‘full of, overly, prone to’, forming adjectives from nouns). The English word can be analysed as vapour + -ous, and is possibly a doublet of hope. Cognates include French vaporeux (“misty, vaporous; filmy, transparent”), Italian vaporoso (“flimsy, gauzy; fluffy; vaporous”), Portuguese vaporoso, and Spanish vaporoso (“airy; vaporous”).