The Collaborative International Dictionary of English v.0.48:

Deipnosophist \Deip*nos"o*phist\ (d[imac]p*n[o^]s"[-o]*f[i^]st),
   n. [Gr. deipnosofisth`s; dei^pnon a meal + sofisth`s a wise
   man, sophist.]
   One of an ancient sect of philosophers, who cultivated
   learned conversation at meals.
   [1913 Webster]

WordNet (r) 3.0 (2006):

deipnosophist
    n 1: someone skilled at informal chitchat