Online Etymology Dictionary:
fair (adj.)Merriam Webster:
O.E. fæger "beautiful, pleasant," from P.Gmc. *fagraz (cf. O.N. fagr, O.H.G. fagar "beautiful," Goth. fagrs "fit"), from PIE *fag-. The meaning in ref. to weather (c.1205) preserves the original sense (opposed to foul). Sense of "light complexioned" (1551) reflects tastes in beauty; sense of "free from bias" (c.1340) evolved from another early meaning, "morally pure, unblemished" (c.1175). The sporting senses (fair ball, fair catch etc.) began in 1856. Fair play is from 1595; fair and square is from 1604. Fair-haired in the fig. sense of "darling, favorite" is from 1909. Fairly in the sense of "somewhat" is from 1805; it earlier meant "totally." Fairway (1584) originally meant "navigational channel of a river;" golfing sense is from 1910. First record of fair-weather friends is from 1736.
6 a: marked by impartiality and honesty : free from self-interest, prejudice, or favoritism b (1): conforming with the established rules : allowed (2): consonant with merit or importance : due c: open to legitimate pursuit, attack, or ridiculeThe definition MW gives for "just" (2 a (1): acting or being in conformity with what is morally upright or good : righteous (2): being what is merited : deserved b: legally correct : lawful) conforms to our understanding of what is legally just.
I ask because some have tried to defined justice in terms of fairness. Level is a kind of equal, but it appears that fair has no link to level.