killer meaning and definition

KILLER noun

Definition of killer (noun)

1. someone who causes the death of a person or animal
   • synonyms: slayer
2. the causal agent resulting in death
   • "heart disease is the biggest killer in the United States"
   • synonyms: cause of death
3. a difficulty that is hard to deal with
   • "that exam was a real killer"
4. predatory black-and-white toothed whale with large dorsal fin; common in cold seas
   • synonyms: grampus, killer whale, orca, Orcinus orca, sea wolf