Source : Webster's Revised Unabridged Dictionary (1913)

Parasitic \Par`a*sit"ic\, Parasitical \Par`a*sit"ic*al\, a. [L.
   parasiticus, Gr. ?: cf. F. parasitique.]
   1. Of the nature of a parasite; fawning for food or favors;
      sycophantic. ``Parasitic preachers.'' --Milton.

   2. (Bot. & Zo["o]l.) Of or pertaining to parasites; living
      on, or deriving nourishment from, some other living animal
      or plant. See {Parasite}, 2 & 3.

   {Parasitic gull}, {Parasitic jager}. (Zo["o]l.) See {Jager}.
      -- {Par`a*sit"ic*al*ly}, adv. -- {Par`a*sit"ic*al*ness},
      n.

Source : WordNet®

parasitic
     adj 1: relating to or caused by parasites; "parasitic infection"
            [syn: {parasitical}]
     2: of or pertaining to epenthesis [syn: {epenthetic}]
     3: of plants or persons; having the nature or habits of a
        parasite or leech; living off another; "a wealthy class
        parasitic upon the labor of the masses"; "parasitic vines
        that strangle the trees"; "bloodsucking blackmailer"; "his
        indolent leechlike existence" [syn: {parasitical}, {leechlike},
         {bloodsucking}]