眨眼
zhǎ yǎn · HSK 7
to blink
😉👁️ 眨 blink + 眼 eye = to blink or wink; eye-blink fast, in the twinkling of an eye
Second character 眼 yǎn means eye and carries the 目 eye radical on its left. Pair it with 眨 blink and the compound literally reads blink-eye, which extends to a wink and to the idiom for something over in the twinkling of an eye.
眼 — eye radical 目 + 艮 (phonetic)
眼 is a semantic-phonetic compound. The left side 目 means 'eye' and gives the meaning, while 艮 on the right supplies the sound. Originally referring to the eyeball, it broadened over time to mean 'eye' generally and, by extension, 'a hole' or 'key point'.