野外
やがい · yagai · JLPT N1 · noun
open air
野 — 里 (village) + 予 (phonetic)
Originally written 埜 (forest 林 over earth 土), depicting wild land beyond cultivated fields. The modern form 野 combines 里 (village/settled land) with 予 as a phonetic component, keeping the meaning of open country, wilderness, or untamed.
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'.