The Agent is the person or entity that performs the action described by a Verb. It is most commonly used in the Passive when the agent is used with 'by':
Eg.: The politician's career was ruined by the scandal.
The scandal performed the act of ruining the politician's career. It is the agent.
"The grammar glossary is the most comprehensive I have seen on the Internet. The definitions are very clear and to the point." ~ Chris Durcan - Editor, The Language Key
