課外
かがい · kagai · JLPT N1 · noun
extracurricular
⚽ 課 (class) + 外 (outside) = activities held outside class = extracurricular
外 — evening 夕 + divination 卜
Originally a compound of 夕 (evening) and 卜 (divination). Ancient Chinese divinations were performed in the morning; doing them at evening (夕) was considered irregular or 'outside' the norm. From this sense of deviation, 外 came to mean 'outside' or 'external'.