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]

The Collaborative International Dictionary of English v.0.48:

Infect \In*fect"\, a. [L. infectus: cf. F. infect. See Infect,
   v. t.]
   Infected. Cf. Enfect. [Obs.] --Shak.
   [1913 Webster]

WordNet (r) 3.0 (2006):

infect
    v 1: communicate a disease to; "Your children have infected you
         with this head cold"
    2: contaminate with a disease or microorganism [syn: infect,
       taint] [ant: disinfect]
    3: corrupt with ideas or an ideology; "society was infected by
       racism"
    4: affect in a contagious way; "His laughter infects everyone
       who is in the same room"

Moby Thesaurus II by Grady Ward, 1.0:

106 Moby Thesaurus words for "infect":
   abuse, activate, adulterate, afflict, aggrieve, alloy, animate,
   befoul, benasty, bewitch, blight, canker, charge, cheapen, coarsen,
   condemn, confound, contaminate, corrupt, crucify, curse, damage,
   debase, debauch, defile, deflower, degenerate, degrade, denature,
   deprave, desecrate, despoil, destroy, devalue, disadvantage,
   disease, disserve, distort, distress, do a mischief, do evil,
   do ill, do wrong, do wrong by, doom, embue, enliven, envenom,
   exhilarate, fire, foul, get into trouble, harass, harm, hex, hurt,
   imbue, impair, inform, infuse, inject, injure, inoculate, inspire,
   inspirit, irradiate, jinx, maltreat, menace, mess, mess up,
   mistreat, misuse, molest, nasty, outrage, persecute, pervert,
   play havoc with, play hob with, poison, pollute, prejudice,
   prostitute, radiumize, ravage, ravish, savage, scathe, spirit,
   spirit up, sully, taint, tarnish, threaten, torment, torture,
   twist, ulcerate, violate, vitiate, vulgarize, warp, wound,
   wreak havoc on, wrong