/ Dictionary / Index G groundless: Meaning and Definition of Find definitions for: ground•less Pronunciation: (ground'lis), [key] — adj. without rational basis: groundless fears. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: groundless (Thesaurus) ground layer ground level Related Content Daily Word Quiz: neologism Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language