1》 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.
2》 a person who works in secret to obtain information for a government.
3》 a person or thing that takes an active role or produces a specified effect.
↘ Grammar the doer of an action.
4》 Computing an independently operating Internet program, typically one set up to locate information on a specified subject and deliver it on a regular basis.
~ive adjective ( Grammar ).
ME: from L. ~- , agere 'to do'.