/ Thesaurus / F Synonyms of fsb Find synonyms for: Noun1. Federal Security Bureau, FSB, Federal Security Service, Russian agencyusage: the internal counterintelligence agency of the Russian Federation and successor to the Soviet KGB; formerly led by Vladimir Putin2. federal savings bank, FSB, savings bankusage: a federally chartered savings bankWordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: tenacious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language