Question

落井下石［乘人之危］　luò jǐnɡ xià shí

Accepted Answer

to continue to attack or injure sb. who is already defeated; to hit or kick a man when he's down:

正面	落井下石［乘人之危］　luò jǐnɡ xià shí
背面	to continue to attack or injure sb. who is already defeated; to hit or kick a man when he's down:

落井下石［乘人之危］ Luò Jǐnɡ Xià Shí Continue Attack Injure Sb