The Collaborative International Dictionary of English v.0.48:

Sedentary \Sed"en*ta*ry\, a. [L. sedentarius, fr. sedere to sit:
   cf. F. se['e]dentaire. See Sedent.]
   1. Accustomed to sit much or long; as, a sedentary man.
      "Sedentary, scholastic sophists." --Bp. Warburton.
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   2. Characterized by, or requiring, much sitting; as, a
      sedentary employment; a sedentary life.
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            Any education that confined itself to sedentary
            pursuits was essentially imperfect.   --Beaconsfield.
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   3. Inactive; motionless; sluggish; hence, calm; tranquil.
      [R.] "The sedentary earth." --Milton.
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            The soul, considered abstractly from its passions,
            is of a remiss, sedentary nature.     --Spectator.
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   4. Caused by long sitting. [Obs.] "Sedentary numbness."
      --Milton.
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   5. (Zool.) Remaining in one place, especially when firmly
      attached to some object; as, the oyster is a sedentary
      mollusk; the barnacles are sedentary crustaceans.
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   Sedentary spider (Zool.), one of a tribe of spiders which
      rest motionless until their prey is caught in their web.
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WordNet (r) 3.0 (2006):

sedentary
    adj 1: requiring sitting or little activity; "forced by illness
           to lead a sedentary life"

Moby Thesaurus II by Grady Ward, 1.0:

46 Moby Thesaurus words for "sedentary":
   abeyant, apathetic, at a standstill, cataleptic, catatonic, dead,
   dopey, dormant, dull, fixed, flat, foul, groggy, heavy, immobile,
   in abeyance, in suspense, inactive, inert, languid, languorous,
   latent, leaden, lifeless, logy, motionless, passive, phlegmatic,
   quiescent, seated, sitting, slack, sleeping, sluggish, slumbering,
   smoldering, stagnant, standing, static, stationary, suspended,
   tame, torpid, unactive, unaroused, unmoving