The Collaborative International Dictionary of English v.0.48:

free enterprise \free enterprise\ n.
   1. an economic system having predominantly private ownership
      of the means of production, and relying chiefly on market
      forces to allocate goods and resources and to determine
      prices, and having a minimum of governmental interference
      in economic decisions; also, the political doctrine
      advocating such a system as the economic system of a
      country. [WordNet sense 1]

   Syn: market economy, laissez-faire economy.
        [WordNet 1.5 +PJC]

   2. The conduct of business according to the principles of the
      free enterprise doctrine; the conduct of economic activity
      without governmental interference.
      [PJC]

WordNet (r) 3.0 (2006):

free enterprise
    n 1: an economy that relies chiefly on market forces to allocate
         goods and resources and to determine prices [syn: market
         economy, free enterprise, private enterprise,
         laissez-faire economy] [ant: non-market economy]

Moby Thesaurus II by Grady Ward, 1.0:

49 Moby Thesaurus words for "free enterprise":
   autarky, bimetallism, bourgeois, capitalism, capitalist,
   capitalistic system, economic self-sufficiency, finance capitalism,
   free competition, free economy, free trade,
   free-enterprise economy, free-enterprise system, governmentalism,
   individualism, individualistic, isolationism, laissez-aller,
   laissez-faire, laissez-faireism, let-alone policy,
   let-alone principle, liberalism, line, localism, managed currency,
   noninterference, nonintervention, nonsocialistic, nullification,
   party line, party principle, planned economy, policy, polity,
   position, price supports, private enterprise, private ownership,
   private sector, private-enterprise, protection, protectionism,
   public policy, pump-priming, rugged individualism, sectionalism,
   self-regulating market, state capitalism