jovial

Short definition from Wiktionary

Adjective

1. 1
   Cheerful and good-humoured; jolly, merry.
2. 2
   Pertaining to the astrological influence of the planet Jupiter; having the characteristics of a person under such influence (see sense 1).
3. 3
   Pertaining to the planet Jupiter; Jovian.
4. 4
   Pertaining to the Roman god Jove or Jupiter (the counterpart of the Greek god Zeus), the god of the sky and thunder and the king of the gods; Jovian.

Noun

1. 1
   An inhabitant of the planet Jupiter; a Jovian.