The Collaborative International Dictionary of English v.0.48:

Philander \Phi*lan"der\, v. i. [Gr. fi`landros fond of men;
   fi`los loving + 'anh`r man.]
   To make love to women; to play the male flirt.
   [1913 Webster]

         You can't go philandering after her again. --G. Eliot.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Philander \Phi*lan"der\, n.
   A lover. [R.] --Congreve.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Philander \Phi*lan"der\, n. (Zool.)
   (a) A South American opossum (Didelphys philander).
   (b) An Australian bandicoot (Perameles lagotis).
       [1913 Webster]

WordNet (r) 3.0 (2006):

philander
    v 1: have amorous affairs; of men; "He has been womanizing for
         years" [syn: philander, womanize, womanise]
    2: talk or behave amorously, without serious intentions; "The
       guys always try to chat up the new secretaries"; "My husband
       never flirts with other women" [syn: chat up, flirt,
       dally, butterfly, coquet, coquette, romance,
       philander, mash]

Moby Thesaurus II by Grady Ward, 1.0:

40 Moby Thesaurus words for "philander":
   Casanova, Don Juan, be promiscuous, cast coquettish glances, chase,
   chase women, chaser, commit adultery, coquet, dally, debauch,
   dissipate, eye, flirt, fool around, fornicate, gallivant, gold-dig,
   grovel, lady-killer, look sweet upon, make eyes at, masher,
   mess around, ogle, philanderer, play around, pursue, rake,
   run around, skirt chaser, sleep around, swing, trifle, wallow,
   wanton, whore, wolf, woman, womanize