Having no basis in fact; unfounded
Without logic; senseless.
Not employed or busy:
Not agreeing with a standard, rule, or measure
The definition of grounded is someone or something stable, sincere, practical or firmly established, or an aircraft or pilot that is being kept from flying.
Capable of reasoning; rational:
Having been demonstrated or verified without doubt:
without reason, justification
Nude, especially unclothed below the waist:
Exposed to the wind and sea; unsheltered.
Find another word for groundless. In this page you can discover 27 synonyms, antonyms, idiomatic expressions, and related words for groundless, like: baseless, unfounded, illogical, chimerical, flimsy, idle, unauthorized, causeless, unjustified, unprovoked and untrue.