The most common and most likely answer to this crossword clue is the 8 letter word SPORTING
I've seen this crossword clue in The Daily Telegraph
S
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More clues leading to the result SPORTING
Buddy explains!

The straight part
We know that "Fair" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case fair = sporting.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does SPORTING mean?
SPORTING verb- To amuse oneself, to play.
- To mock or tease, treat lightly, toy with.
- To display; to have as a notable feature.
- To divert; to amuse; to make merry.
- To represent by any kind of play.
- To practise the diversions of the field or the turf; to be given to betting, as upon races.
- To assume suddenly a new and different character from the rest of the plant or from the type of the species; said of a bud, shoot, plant, or animal.
- To close (a door).
- The act of taking part in a sport.
- Pertaining to sports
- Exhibiting sportsmanship.
- Having a reasonable chance of success.
- Fair, generous; ‘game’.
- (obsolete) Of or relating to unseemly male excesses, especially gambling, prostitution, or similar recreational activities.