1) Disbelieving 2) Distrustful 3) Doubting 4) Incredulous 5) Leery 6) Sceptical 7) Unbelieving 8) Unsure 9) Wary 1) Disbelieving 2) Incredulous 3) Marked by or given to doubt 4) Sceptical 5) Unbelieving 
• (a.) Doubting or denying the truth of revelation, or the sacred Scriptures. • (a.) Of or pertaining to a sceptic or skepticism; characterized by skepticism; hesitating to admit the certainly of doctrines or principles; doubting of everything.
1. Of or pertaining to a sceptic or skepticism; characterised by skepticism; hesitating to admit the certainly of doctrines or principles; doubting of everything. ... 2. Doubting or denying the truth of revelation, or the sacred Scriptures. 'The skeptical system subverts the whole foundation of morals.' (R. Hall) Skep'tacally, Skep'ticalness. ... O...
skeptical, sceptical 1. Tending not to believe or to accept things but to question them. 2. Marked by a doubting attitude. 3. Referring to doubt; questioning; such as, a skeptical attitude or being skeptical of political promises. 4. Relating to or characteristic of skeptics or skepticism.
marked by or given to doubt[Life sciences terms] marked by or given to doubt[SAT terms] marked by or given to doubt[ACT vocabulary] marked by or given to doubt