/ Thesaurus / H Synonyms of hypophosphorous acid Find synonyms for: Noun1. hypophosphorous acid, phosphorous acid, orthophosphorous acid, oxyacid, oxygen acidusage: a clear or yellow monobasic acid (H3PO2)WordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: rustic Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language