agent

n.

1. One who acts for another

   representative, deputy, broker, promoter, operator, salesperson, salesman, assistant, emissary, appointee, proxy, intermediary, executor, attorney, lawyer, go-between, surrogate, procurator, principal, factor, minister, envoy, delegate, spokesperson, spokesman, canvasser, middleman, commissioner, regent, consignee, commissary, syndic, substitute, factotum, steward, functionary, servant, assignee, solicitor, ambassador, diplomat, chargé d'affaires (French), attaché, comprador, proctor, negotiator, advocate, coagent, instrument, tool, cat's paw, press agent, publicity agent, claim agent, employment agent, headhunter*, literary agent, actor's agent, booking agent, flesh peddler*, ten percenter*, handler*, secret agent*, spy*, operative*, double agent*, FBI agent, G-man*, treasury agent, T-man*, narcotics agent, narc*. *

2. An instrumentality

   active force, cause, means, agency; see doer, means 1.

an agent is, generally, a person or thing that acts or is capable of acting, or, in this comparison, one who is empowered to act for another a literary agent; factor, a less common term, now usually denotes an agent for the sale of goods; a deputy is a public official to whom certain authority has been delegated by superiors; proxy implies the delegation of power to substitute for another in some formal or ceremonial act some stockholders vote by proxy