groundless

Adjective

Synonyms: baseless idle unfounded unwarranted wild

WordNet 3.0

Adjective (1)

without a basis in reason or fact“baseless gossip”“the allegations proved groundless”“idle fears”“unfounded suspicions”“unwarranted jealousy”Synonyms: baseless idle unfounded unwarranted wild

Webster's Dictionary (GCIDE)

Groundless \Ground"less\, a. [AS. grundle['a]s bottomless.] Without ground or foundation; wanting cause or reason for support; not authorized; false; baseless; as, groundless fear; a groundless report, rumor, or assertion. -- Ground"less*ly, adv. -- Ground"less*ness, n.