n.
    - a person that provides a particular service, typically one organizing transactions between two other parties. 
▸a person who manages financial or contractual matters for an actor, performer, or writer.
 - a person who works in secret to obtain information for a government.
 - a person or thing that takes an active role or produces a specified effect. 
▸Grammar  the doer of an action.
 - Computing  an independently operating program, typically one that performs background tasks such as information retrieval or processing on behalf of a user or other program.
 
 
  Derivative
  
    
      - agentive adj. (Grammar ).
 
    
   
  Etymology
  ME: from L. agent-, agere ‘to do’.