外れる
はずれる · hazureru · JLPT N3 · verb-ichidan
of gear
🔌 外 = outside + れる: something that has slipped outside its proper slot
The kanji 外 means outside. 外れる is the intransitive partner of 外す (hazusu, to take off), so it means to come off or be out on its own. Hazu-reru, has strayed: a button off, a plug pulled out, a guess that misses.
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'.