Open English Wordnet
Nouns
(n)agentan active and efficient cause; capable of producing a certain effect“their research uncovered new disease agents” (n)agenta representative who acts on behalf of other persons or organizations (n)agenta substance that exerts some force or effect (n)agent, factor, brokera businessman who buys or sells for another in exchange for a commission (n)agentive role, agentthe semantic role of the animate entity that instigates or causes the happening denoted by the verb in the clause 