Killer ( noun , adjective )

(As a noun)

Killer ( noun )

1. A person who kills another person.
2. Something that causes death.

Origin:

Mid 16th century (as a noun denoting a person who kills): from kill + -er.

Examples:

1. The police are searching for the killer.
2. The serial killer was finally caught.
3. He was a notorious killer.
4. Cancer is a silent killer.
5. Lack of sleep can be a killer.

(As an adjective)

Killer ( adjective )

1. Extremely good or effective.
2. Able to cause death.

Origin:

Mid 16th century (as a noun denoting a person who kills): from kill + -er.

Examples:

1. The band had a killer set.
2. He had a killer smile.
3. That was a killer punch.
4. The new drug is a killer for cancer.
5. His presentation skills are killer.