wet·suit also wet suit (w?t?so?ot?)n. A tight-fitting, usually rubber garment designed to keep the body warm in water by trapping water next to the skin, used especially in scuba diving and water sports.American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.