favor

The whole family grows from one Latin verb: favēre, 'to be kindly disposed toward someone.' Picture a Roman crowd at the games — when they favēre a gladiator, they leaned his way, cheering, wishing him well. This is the key to the entire root: favor is never neutral. It is goodwill that tilts in one direction.

The noun favor (Latin favor) named that tilt of goodwill. From it, English drew three threads that all trace back to the same lean:

First, favor itself became 'a kind act' and 'approval.' If I do you a favor, I extend goodwill in a concrete act. If a plan finds favor, it has won approval. And because goodwill that leans toward one person leans away from others, favor also picked up a darker shade: partiality, favoritism — showing favor where it isn't fair.

Second, add the suffix -ite (the one who is...) and you get favorite: the one most favored, the person or thing your goodwill tilts toward above all others. Your favorite song is the one you lean toward every time.

Third, add -able (showing the quality of) and you get favorable: full of favor, giving approval. A favorable review approves; favorable conditions lean in your direction, helping you succeed. Put un- (not) in front and you flip the lean the other way: unfavorable — adverse, leaning against you.

Finally, the past participle favored means 'singled out for favor,' treated with special partiality — the favored candidate is the one goodwill has already chosen.

One wrinkle worth knowing: every core word here has two correct spellings. Americans write favor, favorite, favorable; the British write favour, favourite, favourable. Same word, same meaning — the British kept the -our from Old French (favour), the Americans trimmed it to -or. So if you see 'my favourite colour' in a British novel, it is not a typo; it is the same favorite you already know.