Webster's Revised Unabridged Dictionary · 1913

jovial

jovial , adjective

[French, from Latin Jovialis pertaining to Jove. The planet Jupiter was thought to make those born under it joyful or jovial. See Jove.]

1.
Of or pertaining to the god, or the planet, Jupiter. [capitalized; Obsolete]
Our jovial star reigned at his birth. — Shakespeare
The fixed stars astrologically differenced by the planets, and esteemed Martial or Jovial according to the colors whereby they answer these planets. — Sir T. Browne
2.
Sunny; serene. [Obsolete]
The heavens always joviall. — Spenser
3.
Gay; merry; joyous; jolly; mirth-inspiring; hilarious; characterized by mirth or jollity; as, a jovial youth; a jovial company; a jovial poem.
Be bright and jovial among your guests. — Shakespeare
His odes are some of them panegyrical, others moral; the rest are jovial or bacchanalian. — Dryden

This word is a relic of the belief in planetary influence. Other examples are saturnine, mercurial, martial, lunatic, etc.