訓 かす(か) ・ 音 ビ
Sino-Vietnamese: vi
Hán Việt vi as in vi khuẩn (bacteria) and vi mô (micro): very small. The 彳 radical suggests tiptoeing with tiny steps.
Stroke data: KanjiVG (CC BY-SA 3.0) — kanjivg.tagaini.net
彼は微動だにしなかった。 (かれはびどうだにしなかった)
He didn't move a muscle.