/ Thesaurus / S Synonyms of sleeplessly Find synonyms for: Adverb1. sleeplesslyusage: without sleep; in a sleepless manner; "he was lying in bed sleeplessly"WordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: supine Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language