/ Thesaurus / C Synonyms of clutter up Find synonyms for: Verb1. clutter, clutter up, fill, fill up, make fullusage: fill a space in a disorderly wayWordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: effervescent Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language