con·viv·i·al 
(kən-vĭvē-əl)
(kən-vĭvē-əl)adj.
1. Enjoying good company; sociable. See Synonyms at social.
2. Characterized by merry celebrating; festive: a convivial atmosphere at the reunion.
[Late Latin convīviālis, from Latin convīvium, banquet : com-, com- + vīvere, to live; see gwei- in the Appendix of Indo-European roots.]
con·viv′i·ali·ty (-ălĭ-tē) n.
con·vivi·al·ly adv.