太い
ふとい · futoi · JLPT N5 · i-adj
thick
🐘 futoi: a FOOT that is TOY-sized? No, this foot is fat and thick
太 is 大 (big) plus one extra dot: bigger than big, so fat or thick. The same kanji appears in 太る (futoru, to get fat). Sound hook: fu-to-i runs close to foot-toy, and a fat foot fits no toy shoe.
太 — 大 'big' + extra dot 丶
太 originally derived from 大 ('big, person with arms outstretched') with an added stroke to mean 'greatest' or 'too much'. The extra dot intensifies 大, signaling something beyond merely big. Over time it came to mean 'very', 'too', or 'highest'.