外す
はずす · hazusu · JLPT N3 · verb-godan
to unfasten
🔓👓 外 = outside: hazusu sends a thing outside its fastening, so unclip it
Built on 外 (outside), plus す, which makes it something you do. Common uses: 眼鏡を外す (take off glasses), ボタンを外す (unbutton), 席を外す (step away from your seat). The intransitive partner 外れる means to come off or miss.
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'.