even though
The particle のに is used to express something unexpected or contradictory, similar to 'even though' or 'although'.
Examples
勉強したのに、テストに合格できなかった。
Even though I studied, I couldn't pass the test.
彼は若いのに、すごく上手だ。
Even though he is young, he is very skilled.
雨が降っているのに、学生たちは外で遊んでいる。
Even though it is raining, the students are playing outside.
Quick check
彼は若い___、すごく上手だ。