不由自主 (bù yóu zì zhǔ)

Character breakdown

• 不 (bù) · 4 strokes

  Pictograph of sepals of a flower. The modern meaning "no" is a phonetic loan.

• 由 (yóu) · 5 strokes

  Depicts a kind of helmet worn by warriors. Based on the original meaning "helmet", now written as 胄. The current meaning is a phonetic loan.

• 自 (zì) · 6 strokes

  Pictograph of a nose. Original form of 鼻 (nose). In China, when people point to themselves, they typically point to their nose.

• 主 (zhǔ) · 5 strokes

  Pictograph of a memorial tablet used for spiritual rituals, similar to 示.

Usage

看到那个场景，他不由自主地流下了眼泪。

can't help; involuntarily (idiom)

kàn dào nà ge chǎng jǐng ， tā bù yóu zì zhǔ dì liú xià le yǎn lèi 。