訓 さわ(ぐ),うれい,さわ(がしい) ・ 音 ソウ
Sino-Vietnamese: tao
Horse 馬 plus a simplified 蚤 (flea): a horse bitten by fleas bucks and neighs — noise and uproar, as in Vietnamese tao loạn.
Stroke data: KanjiVG (CC BY-SA 3.0) — kanjivg.tagaini.net
教室で騒いではいけない。 (きょうしつでさわいではいけない)
You must not make noise in the classroom.