/ Thesaurus / A Synonyms of as needed Find synonyms for: Adverb1. as needed, as required, pro re nata, PRNusage: according to need (physicians use PRN in writing prescriptions); "add water as needed"WordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: profiterole Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language