/ Thesaurus / F Synonyms of fallen arch Find synonyms for: Noun1. sunken arch, fallen arch, instepusage: an instep flattened so the entire sole rests on the groundWordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: dormant Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language