/ Thesaurus / F Synonyms of fatten out Find synonyms for: Verb1. fatten, fat, flesh out, fill out, plump, plump out, fatten out, fatten up, change, alter, modifyusage: make fat or plump; "We will plump out that poor starving child"WordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: grimace Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language