/ Thesaurus / I Synonyms of impermanency Find synonyms for: Noun1. impermanence, impermanency, duration, lengthusage: the property of not existing for indefinitely long durationsWordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: penury Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language