ground·less \ˈgrau̇ndlə̇s rapid -nl-\adjective Etymology: Middle English groundeles bottomless, unfathomable, from Old English grundlēas, from grund ground + -lēas -less — more at ground, -less : having no ground or foundation : lacking cause or reason for support < groundless fears > < a groundless charge of treason > • ground·less·lyadverb • ground·less·nessnoun-es