Definition of skeptical:
speculative, undecided, wondering, atheistic, quizzical, inclined to think/believe/agree etc., mistrustful, unconvinced, show-me, bewildered, disbelieving, trustless, doubting, belief, hinky, tentative, suspecting, certain, atheistical, sceptical, questioning, distrustful, unbelieving, unsettled, negativistic, inquisitive, nescient, incredulous.
- disbelieving (part of speech: adjective)
- skeptical (part of speech: adjective)
- incredulous (part of speech: adjective)