Synonyms for Open to doubt:

• adj.

  •questionable (adjective)
  • mysterious,
  • indecisive,
  • fishy,
  • enigmatic,
  • iffy,
  • equivocal,
  • indeterminate,
  • moot,
  • arguable,
  • vague,
  • undefined,
  • problematic,
  • apocryphal,
  • problematical,
  • disputable,
  • occult,
  • cryptic,
  • provisional,
  • oracular,
  • debatable,
  • shady,
  • unreliable,
  • contingent,
  • indefinite,
  • hypothetical,
  • suspect,
  • ambiguous,
  • obscure,
  • unsettled.
  •suspicious (adjective)
  • phony,
  • unusual,
  • overt,
  • irregular,
  • borderline,
  • farfetched,
  • different,
  • uncertain,
  • queer,
  • shaky,
  • peculiar,
  • uncommon,
  • open,
  • too much,
  • unsure,
  • reaching,
  • funny.
  •unbelievable (adjective)
  • cockeyed,
  • implausible,
  • harebrained,
  • staggering,
  • unsubstantial,
  • kooky,
  • outlandish,
  • thick,
  • cockamamie,
  • improbable,
  • Incogitable,
  • for the birds,
  • inconceivable,
  • preposterous,
  • beyond belief,
  • unimaginable,
  • scatterbrained,
  • unconvincing,
  • unthinkable,
  • weak,
  • lamebrained,
  • astonishing,
  • impossible,
  • far-fetched,
  • past belief,
  • incredible,
  • screwy,
  • full of holes,
  • flaky,
  • flimsy,
  • thin,
  • won't hold water.
  •unsubstantiated (adjective)
  • unsupported,
  • uncorroborated.

• Other synonyms:

  •debatable
  • controversial.

Antonyms for Open to doubt:

• adj.

  • questionable
    definite, trusty, proven, trustworthy, Indubious, sure, incontrovertible, certain, undoubted, unquestionable, indisputable, clear.
  • suspicious
    believable, palpable, secure, innocent.
  • unbelievable
    credible, conceivable, tenable, reasonable, possible, likely, plausible, imaginable, real.