/ Thesaurus / D Synonyms of diligently Find synonyms for: Adverb1. diligentlyusage: with diligence; in a diligent manner; "we may diligently observe the Lord's supper on the first day of the week, diligently preach the gospel, or minister to the saint"WordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: heifer Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language