Synonyms for On the face of it:

• adv

  •Other relevant words: (adverb)
  • it would seem,
  • in all likelihood,
  • outwardly,
  • tangibly,
  • it appears that,
  • at a glance,
  • visibly,
  • at first sight,
  • apparently,
  • plausibly,
  • it seems that,
  • presumptively,
  • all appearances,
  • Ostensively,
  • Assumably,
  • to all appearances,
  • speciously,
  • intuitively,
  • in all probability,
  • professedly,
  • presumably.
  •outwardly (adverb)
  • the eye.

• adv.

  •apparently (adverb)
  • probably,
  • superficially,
  • possibly,
  • supposedly,
  • reasonably,
  • as though,
  • as if,
  • allegedly.
  •externally (adverb)
  • clearly.
  •Other relevant words: (adverb)
  • reputably,
  • most likely,
  • hypothetically.
  •outwardly (adverb)
  • to the eye,
  • in appearance,
  • as far as one can see,
  • for all intents and purposes,
  • officially,
  • on the surface.
  •presumably (adverb)
  • credible,
  • theoretically,
  • unquestionably,
  • Doubtlessly,
  • surely,
  • indubitably,
  • doubtless.

• n.

  •Other relevant words: (noun)
  • ostensibly,
  • seemingly.

• Other synonyms:

  •
  • externally.
  •
  • professed.
  •Other relevant words (noun):
  • evidently,
  • prima facie.

Antonyms for On the face of it:

• adv.

  • apparently
    improbably, uncertain, unlikely, dubiously, equivocally, questionably.
  • outwardly
    internally, privately, inside, inwardly.
  • presumably
    doubtfully.