The Collaborative International Dictionary of English v.0.48:

Entrepreneur \En`tre*pre*neur"\, n. [F. See Enterprise.]
   (Polit. Econ.)
   One who takes the initiative to create a product or establish
   a business for profit; generally, whoever undertakes on his
   own account an enterprise in which others are employed and
   risks are taken. --F. A. Walker.
   [1913 Webster +PJC]

WordNet (r) 3.0 (2006):

entrepreneur
    n 1: someone who organizes a business venture and assumes the
         risk for it [syn: entrepreneur, enterpriser]

Moby Thesaurus II by Grady Ward, 1.0:

46 Moby Thesaurus words for "entrepreneur":
   a, administrator, architect, backer, banker, baron, big boss,
   big businessman, business leader, businessman, captain of industry,
   contractor, contriver, designer, developer, deviser, director,
   enterpriser, financier, framer, impresario, industrialist,
   interagent, interceder, intercessor, intermediary, intermediate,
   intermediator, king, little businessman, magnate, man of commerce,
   manager, mediator, middleman, organizer, planner, producer,
   projector, promoter, strategian, strategist, tactician,
   top executive, tycoon, undertaker