The Collaborative International Dictionary of English v.0.48:

Infamy \In"fa*my\, n.; pl. Infamies. [L. infamia, fr. infamis
   infamous; pref. in- not + fama fame: cf. F. infamie. See
   Fame.]
   [1913 Webster]
   1. Total loss of reputation; public disgrace; dishonor;
      ignominy; indignity.
      [1913 Webster]

            The afflicted queen would not yield, and said she
            would not . . . submit to such infamy. --Bp. Burnet.
      [1913 Webster]

   2. A quality which exposes to disgrace; extreme baseness or
      vileness; as, the infamy of an action.
      [1913 Webster]

   3. (Law) That loss of character, or public disgrace, which a
      convict incurs, and by which he is at common law rendered
      incompetent as a witness.
      [1913 Webster]

            Yesterday, Dec. 7, 1941 -- a day which will live in
            infamy, . . .                         --Franklin D.
                                                  Roosevelt.

WordNet (r) 3.0 (2006):

infamy
    n 1: a state of extreme dishonor; "a date which will live in
         infamy"- F.D.Roosevelt; "the name was a by-word of scorn
         and opprobrium throughout the city" [syn: infamy,
         opprobrium] [ant: celebrity, fame, renown]
    2: evil fame or public reputation [ant: fame]