/ Thesaurus / S Synonyms of slacken off Find synonyms for: Verb1. ease up, ease off, slacken off, flag, decrease, diminish, lessen, fallusage: become less intenseWordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: pundit Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language