/ Thesaurus / N Synonyms of nipr Find synonyms for: Noun1. Revolutionary Proletarian Nucleus, Revolutionary Proletarian Initiative Nuclei, NIPRusage: a clandestine group of leftist extremists who oppose Italy's labor policies and foreign policy; responsible for bombing building in the historic center of Rome from 2000 to 2002WordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: agitated Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language