/ Thesaurus / S Synonyms of seif dune Find synonyms for: Noun1. seif dune, dune, sand duneusage: a long and tall sand dune with a sharp crest; common in the SaharaWordNet 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