restraint of trade

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

• noun An action or condition that tends to prevent free competition in business, as the creation of a monopoly or the limiting of a market.

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

• noun law An agreement that prevents fair competition on the open market, such as an agreement by one party to hire a second party to work within a profession on the condition that the second party will not compete against the first.

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

• noun any act that tends to prevent free competition in business