Synonyms for Groundless:

• adj.

  •baseless (adjective)
  • unsupported,
  • unconfirmed,
  • reasonless,
  • uncorroborated,
  • ungrounded,
  • Foundationless.
  •flimsy (adjective)
  • trivial,
  • trifling,
  • in-conceivable,
  • in-adequate,
  • more unpersuasive,
  • un substantial,
  • un believable,
  • un satisfactory,
  • lamest,
  • most controvertible,
  • most unpersuasive,
  • un-substantial,
  • un persuasive,
  • un reasonable,
  • trans parent,
  • in adequate,
  • trans-parent,
  • in credible,
  • un-persuasive,
  • un-believable,
  • un-satisfactory,
  • more controvertible,
  • in conceivable,
  • in-credible,
  • un-reasonable.
  •gratuitous (adjective)
  • in-defensible,
  • un-merited,
  • supererogatory,
  • un essential,
  • most causeless,
  • uncalled for,
  • un provoked,
  • more unprovoked,
  • uncalledfor,
  • un supportable,
  • most unprovoked,
  • un-essential,
  • in-essential,
  • un-provoked,
  • most unmerited,
  • more unmerited,
  • in essential,
  • un merited,
  • un-supportable,
  • in defensible,
  • more causeless.
  •idle (adjective)
  • in-significant,
  • un-availing,
  • most unhelpful,
  • un-productive,
  • un productive,
  • un-necessary,
  • irrelevant,
  • un necessary,
  • idler,
  • un-helpful,
  • un availing,
  • un-successful,
  • un helpful,
  • more unhelpful,
  • un successful,
  • in significant.
  •illogical (adjective)
  • in valid,
  • in conclusive,
  • unproved,
  • un-sound,
  • more self-contradictory,
  • un-soundest,
  • in-congruous,
  • in correct,
  • more self contradictory,
  • most sophistical,
  • un-proved,
  • in-valid,
  • selfcontradictory,
  • in consequent,
  • un-connected,
  • more casuistic,
  • most self-contradictory,
  • un connected,
  • un scientific,
  • in consistent,
  • meaningless,
  • un proved,
  • most self contradictory,
  • most casuistic,
  • in-consequent,
  • in congruous,
  • un sound,
  • in-conclusive,
  • more sophistical,
  • un sounder,
  • off wall,
  • un-sounder,
  • self contradictory,
  • off the wall,
  • more selfcontradictory,
  • in-correct,
  • un-scientific,
  • most selfcontradictory,
  • in-consistent.
  •nonexistent (adjective)
  • Perished,
  • Gossamery,
  • hypothetical,
  • passed on,
  • passed away,
  • null and void,
  • few and far between,
  • Non-existent.
  •unfounded (adjective)
  • off-base,
  • unproven,
  • mendacious.
  •unjustifiable (adjective)
  • un forgivable,
  • un-juster,
  • un juster,
  • un-pardonable,
  • un-conscionable,
  • un-justifiable,
  • in-excusable,
  • un pardonable,
  • in excusable,
  • un-justest,
  • un justest,
  • un-forgivable,
  • un justifiable,
  • un just,
  • un-just,
  • un conscionable.
  •unwarranted (adjective)
  • unwarrantable,
  • unjustifiable.
  •wanton (adjective)
  • more double crossing,
  • most motiveless,
  • most double-crossing,
  • most doublecrossing,
  • more motiveless,
  • un asked,
  • most double crossing,
  • more double-crossing,
  • un-asked.
  •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.

• Other synonyms:

  •
  • bottomless.
  •unproven
  • unverified.
  •unwanted
  • needless.

Paraphrases for Groundless:

• Equivalence

  • Adjective
    unfounded, baseless, unsubstantiated, ill-founded, unjustified, unwarranted, ungrounded, unsupported.

• Independent

  • Adjective
    untrue, well-founded, substantiated, false, indefensible, invalid, unsound, flimsy, unnecessary, flawed, incorrect, justified, inaccurate, undue, irrational, pointless, unjust.
  • Noun, singular or mass
    merit.
  • Verb, past participle
    Grounded, Underpinned, founded, sustained, reinforced, misplaced, built, based, substantiated, flawed, justified.

• Other Related

  • Adjective
    unjustifiable, unreasonable, untenable, gratuitous, unprovoked, frivolous.

Antonyms for Groundless:

• adj.

  • without reason, justification
    justified, right, correct, warranted, proven, reasonable, called-for, Grounded.
  • 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.