疑惑 (yí huò): สงสัย

He was full of doubt, unable to understand why his good friend suddenly stopped talking to him.

The police were doubtful about the man’s statement because his story was contradictory.

Facing the teacher’s question, he looked puzzled, clearly having not previewed the lesson.

The results of this experiment greatly perplexed the scientists, as they completely contradicted the previous theory.