Definition of skeptical :
1. Doubting or denying the truth of revelation, or the sacred Scriptures.
2. Of or pertaining to a sceptic or skepticism; characterized by skepticism; hesitating to admit the certainly of doctrines or principles; doubting of everything.
show-me, tentative, wondering, suspecting, atheistic, bewildered, unconvinced, speculative, negativistic, mistrustful, distrustful, undecided, inclined to think/believe/agree etc., sceptical, hinky, nescient, trustless, quizzical, certain, questioning, belief, inquisitive, atheistical, unsettled
disbelieving (part of speech: adjective)
skeptical (part of speech: adjective)
incredulous (part of speech: adjective)