Yes, fairest is a Scrabble word!

Adjective

1. Free from favoritism or self-interest or bias or deception; conforming with established standards or rules
2. Not excessive or extreme
3. Very pleasing to the eye
4. (of a baseball) hit between the foul lines
5. Lacking exceptional quality or ability
6. Attractively feminine
7. (of a manuscript) having few alterations or corrections
8. Gained or earned without cheating or stealing
9. Free of clouds or rain
10. (used of hair or skin) pale or light-colored;