Third-person singular present of exhaust (to tire out completely; to use up entirely); or plural noun for waste gases or vapors expelled from engines.
From Latin exhaurire (ex- 'out' + haurire 'to draw'). Both the verb and noun forms developed in English by the 16th-17th centuries.
Car exhausts are literally named for what they do—they exhaust (use up) fuel—but the word became famous for environmental damage before most people understood the chemistry of combustion!
Complete word intelligence in one call. Free tier — 50 lookups/day.