/ Thesaurus / L Synonyms of longness Find synonyms for: Noun1. longness, lengthusage: the property of being of long spatial extent; "one gene causes shortness and the other causes longness"2. longness, duration, lengthusage: duration as an extensionWordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: magnanimous Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language