～外
～がい · ～gai · JLPT N2 · noun
out of ~
🚪 Sounds like guy: the guy left outside, as in 予想外 = beyond what was expected
外 as a suffix marks something outside a range: 予想外 (beyond expectations), 専門外 (outside one's field), 時間外 (after hours). The kanji is 夕 evening + 卜 divination: an evening reading fell outside proper practice.
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'.