freelance

from The American Heritage® Dictionary of the English Language, 5th Edition.

• intransitive verb To work as a freelancer.
• intransitive verb To act independently without orders from another.
• intransitive verb To produce and sell as a freelancer.
• noun A freelancer.
• noun An uncommitted independent, as in politics or social life.
• noun A medieval mercenary.

from the GNU version of the Collaborative International Dictionary of English.

• noun a person who acts independently or without authorization of an organization or of his superiors.
• noun a person who pursues a profession independently, and not as the employee of an organization; -- used especially of writers or photographers who sell their work to organizations of which they are not employees.
• adjective of or pertaining to a freelance{2}.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun Someone who sells his services to employers without a long-term contract
• noun A medieval mercenary
• adjective Of, or relating to a freelance; without contract
• verb intransitive To work as a freelance
• verb transitive To produce or sell services as a freelance

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a writer or artist who sells services to different employers without a long-term contract with any of them
• verb work independently and on temporary contracts rather than for a long-term employer
• adjective serving for wages in a foreign army
• adjective working for yourself