a man's suit for casual wear consisting of slacks and a matching shirt or loose-fitting jacket.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
How to use slack suit in a sentence
Somehow she had exchanged the black slack suit for a bright red dress that was even more daring than Eileen's.Luna Escapade | H. B. Fyfe
British Dictionary definitions for slack suit
US casual male dress consisting of slacks and a matching shirt or jacket
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012