To wear out completely. See Synonyms at tire1. To drain of resources or properties; deplete: tobacco crops that exhausted the soil. See Synonyms at deplete. To use up completely: exhausted our funds before the month was out. To treat completely; cover thoroughly: exhaust a topic. To draw out the contents of; drain: exhaust a tank gradually. To let out or draw off: exhaust vaporous wastes through a pipe. To escape or pass out: Steam exhausts through this valve. The escape or release of vaporous waste material, as from an engine. The fumes or gases so released. A duct or pipe through which waste material is emitted. An apparatus for drawing out noxious air or waste material by means of a partial vacuum.