or sweat pants

noun (used with a plural verb)
  1. loose-fitting pants of soft, absorbent fabric, as cotton jersey, usually with a drawstring at the waist and close-fitting or elastic cuffs at the ankles, commonly worn during athletic activity for warmth or to induce sweating.

Origin of sweatpants

First recorded in 1920–25; sweat + pants
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Examples from the Web for sweatpants

Contemporary Examples of sweatpants

Word Origin and History for sweatpants

by 1946, from sweat + pants.

Online Etymology Dictionary, © 2010 Douglas Harper