亡羊补牢

1. • lit. to mend the pen after sheep are lost (idiom)
2. • fig. to act belatedly
3. • better late than never
4. • to lock the stable door after the horse has bolted

Character by character

• 亡(wáng)die
• 羊(yáng)sheep
• 补(bǔ)repair
• 牢(láo)pen