/ Thesaurus / I Synonyms of isn Find synonyms for: Noun1. International Relations and Security Network, ISN, international intelligence agencyusage: Switzerland's information network for security and defense studies and for peace and conflict research and for international relationsWordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: acquiesce Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language