未定
みてい · mitei · JLPT N1 · na-adj
undecided
未 — tree 木 with extra short top stroke
未 originally pictured a tree with luxuriant new branches at the top, suggesting tender shoots not yet matured. From this 'not yet ripe' image it came to mean 'not yet' or 'have not.' It is also the 8th Earthly Branch, used in the traditional sexagenary cycle.
定 — roof 宀 + 正 (correct/upright, phonetic)
Originally written with 宀 (roof) over 正 (upright/correct), suggesting a household settled and orderly under its roof. Over time 正 simplified to 㐬-like form at the bottom, and the meaning shifted from 'settled home' to the broader senses of 'fix, stable, decide.'