Used other than figuratively or idiomatically: see killer, instinct. / (idiomatic) The natural inclination to do whatever is necessary to succeed (including extreme violence)

a person who commits mercy killing

The northern butcher bird.

(linguistics) A dominant and prestigious language which gradually causes extinction of other, especially minor languages.

A murderer who kills two or more victims in a short time in multiple locations.

Alternative form of cop-killer

Alternative form of thrill killer

(idiomatic) A murderer who is motivated by a strong personal desire to have a very exciting experience.

A large wasp (Pompilus formosus) that captures the Texan tarantula (Mygale hentzii) and places it in its nest as food for its young, after paralyzing it by a sting.

Sphecius speciosus, a large digger wasp that hunts cicadas.