接続・逆接N3
〜くせに
even though... (with reproach) / and yet...
Structure
V/い形（普通形）+ くせに；N + の + くせに
Explanation
Expresses a contrast with strong reproach or dissatisfaction, "even though...". Attaches to plain verb/adjective forms or の + noun. More reproachful than のに.
Examples
知っているくせに、教えてくれません。
Even though he knows, he won't tell me.
子供のくせに、大人みたいなことを言います。
He's just a kid, yet he talks like an adult.
Note
くせに carries strong reproach and is colloquial; the main clause should not describe the speaker's own action.