/ Thesaurus / S Synonyms of sustainment Find synonyms for: Noun1. sustenance, sustentation, sustainment, maintenance, upkeep, supportusage: the act of sustaining life by food or providing a means of subsistence; "they were in want of sustenance"; "fishing was their main sustainment"WordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: confectionery Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language