beast

A beast is a large animal.

Example: It isn't fit for man nor beast out there.

A beast is a monster.

Example: There was a terrible beast in the movie.

If something is a beast it is very difficult or unpleasant.

Example: Yes, this language is a beast.

If something is a beast it is very big or powerful.

Example: The truck he drove was huge, a real beast.

If a person is a beast, they are wild, violent or uncivilized.

Example: How dare you touch me like that! You beast!