skeptical; incredulous
Describes a doubting or questioning attitude toward claims, ideas, or appearances. Often used with ～な態度 or ～に見る.
He showed a skeptical attitude toward the explanation.
Hearing that story, I became incredulous.
Compound of 懐疑 (かいぎ, 'doubt, skepticism') + 的 (てき, '-like, -ish'). 懐疑 is a Sino-Japanese word from Middle Chinese elements meaning 'to harbor doubt'.