Source : Webster's Revised Unabridged Dictionary (1913)

Merrymaking \Mer"ry*mak`ing\, n.
   The act of making merry; conviviality; merriment; jollity.
   --Wordsworth.

Merrymaking \Mer"ry*mak`ing\, a.
   Making or producing mirth; convivial; jolly.

Source : WordNet®

merrymaking
     n : a boisterous celebration; a merry festivity [syn: {conviviality},
          {jollification}]