What does "ambulance chaser" mean?

An attorney who seeks to profit from someone's injury or accident; also, an inferior lawyer. For example, Karen refused to join any law firm that included ambulance chasers. The practice of suing for damages on behalf of the injured person in exchange for a contingency fee—usually a large percentage of the amount so won—may be older, but this derogatory term began to be used for lawyers who actively sought out individuals injured in accidents who required an ambulance. [Slang; late 1800s]