heat exhaustion

WordReference Random House Unabridged Dictionary of American English © 2025

heat′ exhaus′tion, 

1. Pathology a condition characterized by faintness, rapid pulse, nausea, profuse sweating, cool skin, and collapse, caused by prolonged exposure to heat accompanied by loss of adequate fluid and salt from the body. Also called heat prostration. 

• 1935–40

Collins Concise English Dictionary © HarperCollins Publishers::

heat exhaustion noun

1. a condition resulting from exposure to intense heat, characterized by dizziness, abdominal cramp, and prostration
   Compare heatstroke