The Collaborative International Dictionary of English v.0.48:

Convivial \Con*viv"i*al\ (?; 277), a. [From L. convivium a
   feast; con- + vivere to live. See Victuals, and cf.
   Convive.]
   Of or relating to a feast or entertainment, or to eating and
   drinking, with accompanying festivity; festive; social; gay;
   jovial.
   [1913 Webster]

         Which feasts convivial meetings we did name. --Denham.
   [1913 Webster]

WordNet (r) 3.0 (2006):

convivial
    adj 1: occupied with or fond of the pleasures of good company;
           "a convivial atmosphere at the reunion"; "a woman of
           convivial nature"; "he was a real good-time Charlie"
           [syn: convivial, good-time]

Moby Thesaurus II by Grady Ward, 1.0:

22 Moby Thesaurus words for "convivial":
   boon, companionable, festal, festive, free and easy, gala, gay,
   gladsome, hail-fellow-well-met, hearty, hilarious, jocund, jolly,
   jovial, joyful, joyous, lively, merry, merrymaking, on the loose,
   sociable, vivacious