The Collaborative International Dictionary of English v.0.48:

Casanova \Casanova\ n.
   1. an Italian adventurer (Giovanni Giacomo Casanova; b. 1725;
      d. 1798) who wrote vivid accounts of his sexual
      encounters.
      [WordNet 1.5]

   2. any man noted for his amorous adventures.
      [WordNet 1.5]

WordNet (r) 3.0 (2006):

Casanova
    n 1: an Italian adventurer who wrote vivid accounts of his
         sexual encounters (1725-1798) [syn: Casanova, Giovanni
         Jacopo Casanova, Casanova de Seingalt, Giovanni Jacopo
         Casanova de Seingalt]
    2: any man noted for his amorous adventures