Source : Webster's Revised Unabridged Dictionary (1913)

Anonymous \A*non"y*mous\, a. [Gr. ? without name; 'an priv. + ?,
   Eol. for ? name. See {Name}.]
   Nameless; of unknown name; also, of unknown or unavowed
   authorship; as, an anonymous benefactor; an anonymous
   pamphlet or letter.

Source : WordNet®

anonymous
     adj 1: having no known name or identity or known source; "anonymous
            authors"; "anonymous donors"; "an anonymous gift"
            [syn: {anon.}] [ant: {onymous}]
     2: not known or lacking marked individuality; "brown anonymous
        houses"; "anonymous bureaucrats in the Civil Service"