Translation guide
How to express suspicion toward a person, statement, or situation in Japanese, from mild doubt to strong distrust.
Expressing that you feel something is not right or that someone may be hiding something.
The most direct and common verb for 'to suspect' or 'to doubt'. Can be used for people, statements, or situations.
彼の話を疑っている。
I'm suspicious of his story.
彼女が嘘をついていると疑う。
I suspect she is lying.
Literally 'think it's suspicious'. Very natural for expressing a gut feeling that something is off.
あの人はちょっと怪しいと思う。
I'm a bit suspicious of that person.
この話は怪しいと思う。
I think this story is suspicious.
A noun meaning 'suspicion' or 'doubt', often used in formal or news contexts. Commonly used with 持つ (to have).
彼に対して疑惑を持っている。
I have suspicions about him.
Suspecting someone of a specific bad act, like cheating, stealing, or lying.
Pattern: [person] を疑う. Directly suspect someone of something. The specific act is often implied or stated with ～のではないか.
彼を疑っている。
I'm suspicious of him.
彼がカンニングしたのではないかと疑っている。
I suspect he cheated on the exam.
Verb meaning 'to suspect' or 'to be suspicious of', slightly more formal than 疑う. Often used when you find someone's behavior questionable.
Literally 'cast doubt on'. Used when you openly express suspicion toward someone.
彼に疑いをかけるのは失礼だ。
It's rude to be suspicious of him.
Being cautious because you suspect potential danger or trickery.
Means 'to be on guard' or 'to be wary'. Used when you are cautious about a person or situation that might be harmful.
あの男には警戒している。
I'm suspicious of that man (and being careful).
Means 'to be careful' or 'to be cautious'. Implies taking precautions because you suspect something might go wrong.
詐欺かもしれないから用心している。
I'm being cautious because it might be a scam.
Playfully suggesting someone is up to something, often among friends.
Adjective meaning 'suspicious', 'shady', or 'dubious'. Can be used lightly among friends.
お前、なんか怪しいな。
You seem suspicious (joking).
In English, 'be suspicious of' often implies active distrust. In Japanese, 疑う can mean both 'suspect' and 'doubt'. Context clarifies which is meant. For simple disbelief, 信じない (I don't believe) may be clearer.
疑う is a direct verb for suspecting someone or something. 怪しいと思う is more about your impression that something is off. Use 疑う when you have a specific target of suspicion; use 怪しいと思う for a vague feeling.
彼が犯人だと疑っている。
I suspect he is the culprit.
この状況は怪しいと思う。
I think this situation is suspicious.
彼の行動を怪しんでいる。
I'm suspicious of his behavior.
Colloquial adjective meaning 'fishy' or 'shady'. Stronger than 怪しい, often implies distrust.
あのセールスマン、胡散臭いね。
That salesman seems really suspicious.