Shark (noun)

1. A large fish with a pointed snout and sharp teeth, living in salt water and preying on other fish and sometimes on swimmers and divers.
2. A predatory person or organization.
3. A person who is unscrupulous and ruthless in business or personal dealings.
4. A person who is considered to be dangerous and exploitative.

Origin:

Old english scearc, of germanic origin; related to dutch schaar and german schurke "villain", also to sharp.

Examples:

1. The shark is a powerful predator.
2. The shark is a dangerous animal.
3. He is a shark in business.
4. The shark swam around the boat.
5. The shark attacks on swimmers were reported.