Contrast, With an Accusation
くせに marks a contradiction the speaker resents. It is のに with contempt added.
- 知っているくせに、教えてくれなかった。(He knew, and still wouldn't tell me.)
The blame is not optional. You cannot use くせに neutrally.
Against のに
| Pattern | Feel |
|---|---|
| 若い**のに**しっかりしている | surprise, often admiring |
| 若いくせに生意気だ | disapproval |
のに can carry either warmth or complaint. くせに only complains.
The Subject Restriction
Both halves must describe the same person, and that person is normally not you:
- ○ 彼は下手なくせに自信がある。
- × 雨が降っているくせに出かけた。
Weather has no character to criticise. Use のに for situations, くせに for people.
Attaching It
| Type | Form |
|---|---|
| Verb | 知っているくせに |
| い-adjective | 若いくせに |
| な-adjective | 下手なくせに |
| Noun | 子供のくせに |
Register Warning
くせに is rude. It is fine between friends and family, and it appears constantly in drama and manga, but directed at a colleague or a superior it is a genuine insult. When you want the contrast without the sting, use のに.