/ Dictionary / Index S slack suit: Meaning and Definition of Find definitions for: slack' suit" Pronunciation: [key] a man's suit for casual wear consisting of slacks and a matching shirt or loose-fitting jacket. pantsuit. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. slacks slack water Related Content Daily Word Quiz: neologism Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language