countermurder means A murder in response to another murder. Lexicurio rates it Sui generis — a strength score of 87 out of 100.
Etymology
From counter- + murder.
noun
- A murder in response to another murder.“I go out with him on tour in his armored car through Bujumbura's ethnically cleansed neighborhoods to talk to the adolescents with the Kalashnikovs and grenades, who for the price of a few beers will firebomb a street. He gets out and confronts them, telling them that the cycle of murder and countermurder must stop, or they will all be swept away.”