/ Thesaurus / I Synonyms of imperviousness Find synonyms for: Noun1. impenetrability, imperviousness, qualityusage: the quality of being impenetrable (by people or light or missiles etc.)WordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: procrastinate Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language