The Collaborative International Dictionary of English v.0.48:

Use \Use\, v. t. [imp. & p. p. Used; p. pr. & vb. n. Using.]
   [OE. usen, F. user to use, use up, wear out, LL. usare to
   use, from L. uti, p. p. usus, to use, OL. oeti, oesus; of
   uncertain origin. Cf. Utility.]
   [1913 Webster]
   1. To make use of; to convert to one's service; to avail
      one's self of; to employ; to put a purpose; as, to use a
      plow; to use a chair; to use time; to use flour for food;
      to use water for irrigation.
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            Launcelot Gobbo, use your legs.       --Shak.
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            Some other means I have which may be used. --Milton.
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   2. To behave toward; to act with regard to; to treat; as, to
      use a beast cruelly. "I will use him well." --Shak.
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            How wouldst thou use me now?          --Milton.
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            Cato has used me ill.                 --Addison.
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   3. To practice customarily; to make a practice of; as, to use
      diligence in business.
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            Use hospitality one to another.       --1 Pet. iv.
                                                  9.
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   4. To accustom; to habituate; to render familiar by practice;
      to inure; -- employed chiefly in the passive participle;
      as, men used to cold and hunger; soldiers used to
      hardships and danger.
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            I am so used in the fire to blow.     --Chaucer.
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            Thou with thy compeers,
            Used to the yoke, draw'st his triumphant wheels.
                                                  --Milton.
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   To use one's self, to behave. [Obs.] "Pray, forgive me, if
      I have used myself unmannerly." --Shak.

   To use up.
      (a) To consume or exhaust by using; to leave nothing of;
          as, to use up the supplies.
      (b) To exhaust; to tire out; to leave no capacity of force
          or use in; to overthrow; as, he was used up by
          fatigue. [Colloq.]
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   Syn: Employ.

   Usage: Use, Employ. We use a thing, or make use of it,
          when we derive from it some enjoyment or service. We
          employ it when we turn that service into a particular
          channel. We use words to express our general meaning;
          we employ certain technical terms in reference to a
          given subject. To make use of, implies passivity in
          the thing; as, to make use of a pen; and hence there
          is often a material difference between the two words
          when applied to persons. To speak of "making use of
          another" generally implies a degrading idea, as if we
          had used him as a tool; while employ has no such
          sense. A confidential friend is employed to negotiate;
          an inferior agent is made use of on an intrigue.
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                I would, my son, that thou wouldst use the power
                Which thy discretion gives thee, to control
                And manage all.                   --Cowper.
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                To study nature will thy time employ:
                Knowledge and innocence are perfect joy.
                                                  --Dryden.
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WordNet (r) 3.0 (2006):

used
    adj 1: employed in accomplishing something; "the principle of
           surprise is the most used and misused of all the
           principles of war"- H.H.Arnold & I.C.Eaker [ant:
           misused]
    2: of persons; taken advantage of; "after going out of his way
       to help his friend get the job he felt not appreciated but
       used" [syn: exploited, ill-used, put-upon, used,
       victimized, victimised]
    3: previously used or owned by another; "bought a secondhand (or
       used) car" [syn: secondhand, used]

Moby Thesaurus II by Grady Ward, 1.0:

43 Moby Thesaurus words for "used":
   ablated, acquainted with, adapted to, applied, by the board,
   cast-off, consumed, depleted, dissipated, down the drain, employed,
   eroded, exercised, exerted, expended, familiar with, forfeit,
   forfeited, gone, gone to waste, hand-me-down, in use,
   irretrievable, long-lost, lost, lost to, misspent, not new,
   occupied, old, out the window, pawed-over, run to seed, secondhand,
   shrunken, spent, squandered, unnew, used to, used up, wasted, worn,
   worn away