呆
dāi · HSK 5
foolish
😶 呆 = 口 (mouth) + 木 (wood/tree) — a mouth as wooden as a tree, blank and dumbstruck
The character stacks 口 on top of 木: a face whose mouth has gone wooden. From there it extends to dazed, dull-witted, or just standing there stupefied — as in 发呆 (to space out).
呆 — mouth 口 + tree/wood 木
Originally a variant of 保 (to protect), depicting a person carrying a child. Over time the form simplified to 口 over 木 and the meaning shifted to 'dull, foolish, stunned.' Today 呆 mainly means dumbstruck or slow-witted, as in 发呆 (to space out).