Synonyms for Mirthful (same or very similar meaning)
WordNet sense 1 (full of or showing high-spirited merriment):
jocund, jolly, jovial, merryWordNet sense 2 (full of or characterized by joy):
joyousWordNet sense 3 (arousing or provoking laughter):
amusing, comic, comical, funny, laughable, risibleWordNet sense 4 (full of or characterized by humor):
humorous, humourousFrom the ODE community, based on WordNetadd/edit