訓 き(く) ・ 音 コウ
漢越音: hiệu
力 (strength) on the right for meaning, 交 for the sound kou. Effort that actually produces a result is effectiveness: kouka, an effect.
Stroke data: KanjiVG (CC BY-SA 3.0) — kanjivg.tagaini.net
この薬はよく効きます。 (このくすりはよくききます)
This medicine works well.