之外
zhīwài · HSK 5
beyond
🚪➡️ 之外 = of + outside; marks what lies outside a set
之 is a classical genitive particle (of/its) and 外 means outside or beyond. Together 之外 literally reads as 'the outside of' — used after a noun to mean 'apart from X' or 'beyond X'.
之 — foot 止 above ground line 一
Originally a pictograph of a foot (止) stepping forward from a baseline, meaning 'to go' or 'to proceed'. Over time the concrete 'going' sense faded, and 之 was borrowed as a grammatical particle marking possession ('of') or as a pronoun ('it'), which became its dominant use in Classical Chinese.
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'.