/ Thesaurus / L Synonyms of lump sum Find synonyms for: Noun1. lump sum, paymentusage: a complete payment consisting of a single sum of moneyWordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: dormant Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language