The Collaborative International Dictionary of English v.0.48:

Nobody \No"bod*y\, n.; pl. Nobodies. [No, a. + body.]
   1. No person; no one; not anybody.
      [1913 Webster]

   2. Hence: A person of no influence or importance; an
      insignificant or contemptible person. [Colloq.]
      [1913 Webster]

WordNet (r) 3.0 (2006):

nobody
    n 1: a person of no influence [syn: cipher, cypher,
         nobody, nonentity]