/ Thesaurus / S Synonyms of security deposit Find synonyms for: Noun1. margin, security deposit, down payment, depositusage: the amount of collateral a customer deposits with a broker when borrowing from the broker to buy securitiesWordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: lyre Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language