The Collaborative International Dictionary of English v.0.48:

Vegetate \Veg"e*tate\, v. i. [imp. & p. p. Vegetated; p. pr. &
   vb. n. Vegetating.] [L. vegetatus, p. p. of vegetare to
   enliven. See Vegetable.]
   [1913 Webster]
   1. To grow, as plants, by nutriment imbibed by means of roots
      and leaves; to start into growth; to sprout; to germinate.
      [1913 Webster]

            See dying vegetables life sustain,
            See life dissolving vegetate again.   --Pope.
      [1913 Webster]

   2. Fig.: To lead a life too low for an animate creature; to
      do nothing but eat and grow. --Cowper.
      [1913 Webster]

            Persons who . . . would have vegetated stupidly in
            the places where fortune had fixed them. --Jeffrey.
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   3. (Med.) To grow exuberantly; to produce fleshy or warty
      outgrowths; as, a vegetating papule.
      [1913 Webster]

WordNet (r) 3.0 (2006):

vegetate
    v 1: lead a passive existence without using one's body or mind
    2: establish vegetation on; "They vegetated the hills behind
       their house"
    3: produce vegetation; "The fields vegetate vigorously"
    4: grow like a plant; "This fungus usually vegetates vigorously"
    5: grow or spread abnormally; "warts and polyps can vegetate if
       not removed"
    6: propagate asexually; "The bacterial growth vegetated along"
    7: engage in passive relaxation; "After a hard day's work, I
       vegetate in front of the television" [syn: vege out,
       vegetate]