The Collaborative International Dictionary of English v.0.48:

Conversationist \Con`ver*sa"tion*ist\, n.
   One who converses much, or who excels in conversation.
   --Byron.
   [1913 Webster]

WordNet (r) 3.0 (2006):

conversationist
    n 1: someone skilled at conversation [syn: conversationalist,
         conversationist, schmoozer]