/ Dictionary / Index S slacken: Meaning and Definition of Find definitions for: slack•en Pronunciation: (slak'un), [key] — v.t., v.i. to make or become less active, vigorous, intense, etc. to make or become looser or less taut. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: slacken (Thesaurus) slack-baked slacker 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