The Collaborative International Dictionary of English v.0.48:

Consumer \Con*sum"er\ (k[o^]n*s[=u]m"[~e]r), n.
   1. One who, or that which, consumes; as, the consumer of
      food.
      [1913 Webster]

   2. (Econ.) the person or organization that uses some item of
      commerce or service in its own acitities, as opposed to
      reselling the item or including it as part of another item
      for resale; -- called also the end user.
      [PJC]

WordNet (r) 3.0 (2006):

consumer
    n 1: a person who uses goods or services

Moby Thesaurus II by Grady Ward, 1.0:

53 Moby Thesaurus words for "consumer":
   Brillat-Savarin, Lucullus, board-and-roomer, boarder, bon vivant,
   browser, buyer, cannibal, carnivore, connoisseur of food,
   customer agent, diner, diner-out, eater, eater-out, employer,
   emptor, enjoyer, epicure, feeder, flesh-eater, fruitarian,
   gastronome, glutton, gourmand, gourmet, grain-eater, graminivore,
   granivore, herbivore, high liver, hungry mouth, lactovegetarian,
   luncher, man-eater, marketer, meat-eater, mouth, omnivore,
   omophagist, pantophagist, phytophage, picnicker, plant-eater,
   predacean, purchaser, purchasing agent, shopper, trencherman, user,
   vegetarian, vendee, window-shopper