c.1300, "attractiveness, charm," from Old French favor (13c., Modern French faveur) "favor, approval, partiality," from Latin favorem (nominative favor) "good will, inclination, partiality, support," coined by Cicero from stem of favere "to show kindness to," from PIE *ghow-e- "to honor, revere, worship." Meaning "act of kindness" is from late 14c. Meaning "thing given as a mark of favor" is from 1580s. Phrase in favor of recorded from 1560s.
"to regard with favor, indulge, treat with partiality," mid-14c., from Old French favorer, from favor (see favor (n.)). Related: Favored; favoring.