Meaning : Someone who causes the death of a person or animal.
Synonyms : slayer
Meaning : The causal agent resulting in death.
Example :
Heart disease is the biggest killer in the United States.
Synonyms : cause of death
Meaning : A difficulty that is hard to deal with.
Example :
That exam was a real killer.
Meaning : Predatory black-and-white toothed whale with large dorsal fin. Common in cold seas.
Synonyms : grampus, killer whale, orca, orcinus orca, sea wolf