【Merry】 , 【blithe】 , 【jocund】 , 【jovial】 , 【jolly】 mean indicating or showing high spirits or lightheartedness often in play and laughter.
【Merry】 implies a gay, cheerful temper or mood and uninhibited enjoyment of frolic, festivity, or fun of any sort.
【Blithe】 carries a stronger implication of freshness, buoyancy, and lightheartedness than 【merry】 ; it usually suggests carefree, innocent, or even heedless gaiety.
【Jocund】 heightens the implication of gladness and usually also connotes liveliness, exhilaration of spirits, or elation.
【Jovial】 connotes especially good-fellowship or conviviality.
【Jolly】 often suggests higher spirits than 【jovial】 and an even more manifest attempt to keep others laughing (as by jesting, bantering, and playing tricks).