agent
- n an active and efficient cause; capable of producing a certain effect
their research uncovered new disease agents - n a representative who acts on behalf of other persons or organizations
- n a substance that exerts some force or effect
- n a businessman who buys or sells for another in exchange for a commission
- n any agent or representative of a federal agency or bureau
- n the semantic role of the animate entity that instigates or causes the happening denoted by the verb in the clause