Merriam-Webster has 11 true definitions of 'fair.'
Definition of fair
1

leasing to the eye or mind especially because of fresh, charming, or flawless quality The innkeeper had two fair daughters.
2 :superficially pleasing :specious she trusted his fair promises
3 a :clean, pure fair sparkling water
b :clear, legible an old manuscript written in a fair hand
4 :not stormy or foul :fine fair weather
5 :ample a fair estate
6 a :marked by impartiality and honesty :free from self-interest, prejudice, or favoritism a very fair person to do business with
b (1) :conforming with the established rules :allowed (2) :consonant with merit or importance :due a fair share
c

pen to legitimate pursuit, attack, or ridicule fair game
7 a

romising, likely in a fair way to win
b :favorable to a ship's course a fair wind
8 archaic :free of obstacles
9 :not dark fair skin a person of fair complexion
10 a :not very good or very bad

f average or acceptable quality Her work was only fair. a patient in upgraded from serious to fair condition
b :sufficient but not ample :adequate a fair understanding of the work a fair chance of winning
c :moderately numerous, large, or significant takes a fair amount of time a fair number of participants
11 :being such to the utmost :utter
a fair treat to watch him—New Republic
I think your best bet is 6(b)(2), but it's a stretch.
I'm OK with that one, but am more going with 6(a) and 6(b)(1).
Anyway, it's all 6(c)