The Collaborative International Dictionary of English v.0.48:

man of the world \man of the world\ n.
   A worldly-wise person; a sophisticate.
   [WordNet 1.5]

WordNet (r) 3.0 (2006):

man of the world
    n 1: a worldly-wise person [syn: sophisticate, man of the
         world]

Moby Thesaurus II by Grady Ward, 1.0:

27 Moby Thesaurus words for "man of the world":
   Beau Brummel, arbiter of fashion, city slicker, clotheshorse,
   clubman, clubwoman, cosmopolitan, cosmopolite, dandy, deb,
   debutante, fashion plate, fashionable, fop, man of experience,
   man-about-town, mondain, mondaine, slicker, socialite,
   sophisticate, subdeb, subdebutante, swinger, taste-maker,
   tone-setter, trend-setter