The Collaborative International Dictionary of English v.0.48:

Infect \In*fect"\, v. t. [imp. & p. p. Infected; p. pr. & vb.
   n. Infecting.] [L. infectus, p. p. of inficere to put or
   dip into, to stain, infect; pref. in- in + facere to make;
   cf. F. infecter. See Fact.]
   [1913 Webster]
   1. To taint with morbid matter or any pestilential or noxious
      substance or effluvium by which disease is produced; as,
      to infect a lancet; to infect an apartment.
      [1913 Webster]

   2. To affect with infectious disease; to communicate
      infection to; as, infected with the plague.
      [1913 Webster]

            Them that were left alive being infected with this
            disease.                              --Sir T.
                                                  North.
      [1913 Webster]

   3. To communicate to or affect with, as qualities or
      emotions, esp. bad qualities; to corrupt; to contaminate;
      to taint by the communication of anything noxious or
      pernicious. --Cowper.
      [1913 Webster]

            Infected Ston's daughters with like heat. --Milton.
      [1913 Webster]

   4. (Law) To contaminate with illegality or to expose to
      penalty.

   Syn: To poison; vitiate; pollute; defile.
        [1913 Webster]

WordNet (r) 3.0 (2006):

infected
    adj 1: containing or resulting from disease-causing organisms;
           "a septic sore throat"; "a septic environment"; "septic
           sewage" [syn: septic, infected] [ant: antiseptic]

Moby Thesaurus II by Grady Ward, 1.0:

40 Moby Thesaurus words for "infected":
   activated, autoluminescent, bad, cankered, charged, contaminated,
   corrupted, diseased, gangrened, gangrenous, hot, impure,
   irradiated, morbid, mortified, nonkosher, pathological, peccant,
   poisoned, polluted, radiferous, radioactivated, radioactive,
   radioluminescent, ritually unclean, septic, sphacelated, tainted,
   tref, ulcerated, ulcerous, unbathed, unclean, uncleanly, unpure,
   unscoured, unscrubbed, unswept, unwashed, unwiped