/ Thesaurus / F Synonyms of foster brother Find synonyms for: Noun1. foster-brother, foster brother, male, male personusage: your foster brother is a male who is not a son of your parents but who is raised by your parentsWordNet 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