前車之鑑

1. • a warning taken from the overturned cart ahead (idiom)

     lit.

2. • lesson learned from past mistakes or failures

     fig.

Character by character

• 前(qián)front
• 車(chē)surname Che
• 之(zhī)(possessive particle, literary equivalent of 的 de)
• 鑑(jiàn)bronze mirror