Definition for Groundless:

• Without foundation; without reason; as, groundless fears.

Synonyms for Groundless:

• adj.

  •baseless (adjective)
  • uncorroborated,
  • ungrounded,
  • Foundationless,
  • unsupported,
  • unconfirmed.
  •nonexistent (adjective)
  • hypothetical.
  •unfounded (adjective)
  • unproven.
  •unwarranted (adjective)
  • unwarrantable,
  • unjustifiable.
  •without reason, justification (adjective)
  • empty,
  • imaginary,
  • chimerical,
  • unauthorized,
  • false,
  • illusory,
  • unjustified,
  • uncalled-for.

• n.

  •
  • allegedly,
  • doubtful,
  • alleged,
  • seemingly,
  • anecdotal,
  • apparently,
  • supposed,
  • speculative.
  •causeless (noun)
  • illogical.
  •groundless (noun)
  • unwarranted.

Antonyms for Groundless:

• adj.

  • without reason, justification
    real, warranted, reasonable, right, genuine, called-for, correct, Grounded, substantiated, proven, justified.
  • Other antonyms:
    confirmed, wise, validated, true, genuine, substantiated, verified, sound, actual, sure, informed, sensible, sane, certified, well-grounded, certain, hard, credible, corroborated, plausible, real, clear.