The Collaborative International Dictionary of English v.0.48:

Utilitarian \U*til`i*ta"ri*an\, a. [See Utility.]
   [1913 Webster]
   1. Of or pertaining to utility; consisting in utility; ?iming
      at utility as distinguished from beauty, ornament, etc.;
      sometimes, reproachfully, evincing, or characterized by, a
      regard for utility of a lower kind, or marked by a sordid
      spirit; as, utilitarian narrowness; a utilitarian
      indifference to art.
      [1913 Webster]

   2. Of or pertaining to utilitarianism; supporting
      utilitarianism; as, the utilitarian view of morality; the
      Utilitarian Society. --J. S. Mill.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Utilitarian \U*til`i*ta"ri*an\, n.
   One who holds the doctrine of utilitarianism.
   [1913 Webster]

         The utilitarians are for merging all the particular
         virtues into one, and would substitute in their place
         the greatest usefulness, as the alone principle to
         which every question respecting the morality of actions
         should be referred.                      --Chalmers.
   [1913 Webster]

         But what is a utilitarian? Simply one who prefers the
         useful to the useless; and who does not? --Sir W.
                                                  Hamilton.
   [1913 Webster]

WordNet (r) 3.0 (2006):

utilitarian
    adj 1: having a useful function; "utilitarian steel tables"
           [syn: utilitarian, useful]
    2: having utility often to the exclusion of values; "plain
       utilitarian kitchenware"
    n 1: someone who believes that the value of a thing depends on
         its utility

Moby Thesaurus II by Grady Ward, 1.0:

77 Moby Thesaurus words for "utilitarian":
   Cyrenaic, Eleatic, Epicurean, Megarian, Stoic, advantageous,
   animist, animistic, appropriate, atomistic, banausic, beneficial,
   breadwinning, businesslike, commercial, commodious, cosmotheistic,
   down-to-earth, eclectic, empirical, employable, eudaemonistic,
   existential, expedient, fitting, functional, good for, hard,
   hedonic, hedonist, hedonistic, helpful, humanist, humanistic,
   idealistic, instrumentalist, materialistic, matter-of-fact,
   mechanistic, metaphysical, moneymaking, monistic, naturalistic,
   nominalist, of general utility, of help, of service, of use,
   panlogistical, pantheistic, positivist, positivistic, practical,
   pragmatic, pragmatical, pragmatist, proper, prosaic, rationalistic,
   realist, realistic, scholastic, sensationalistic, serviceable,
   syncretistic, theistic, transcendentalist, transcendentalistic,
   unidealistic, unromantic, useful, vitalistic, voluntarist,
   voluntaristic, workaday, workday, working