Apt to distrust; suspicious; mistrustful.

having or showing distrust; "a man of distrustful nature"; "my experience...in other fields of law has made me distrustful of rules of thumb generally"- B.N.Cardozo; "vigilant and distrustful superintendence"- Thomas Jefferson

incredulous by virtue of distrust

Not confident; diffident; wanting confidence or thrust; modest; as, distrustful of ourselves, of one's powers.