The most common and most likely answer to this crossword clue is the 8 letter word MISMATCH
I've seen this crossword clue in The Daily Telegraph
M
I
S
M
A
T
C
H
More clues leading to the result MISMATCH
- Is game of football pursuing male conflict?
- Don’t go and overlook marriage, they said
- Conflict causes female to lose stone at first, getting lighter
- Optimism at Chequers disguising conflict
- Self-esteem finally is thing that ignites unequal contest
- Create bad marriage contributing to pessimism at church
- Unfair contest? Short young lady lighter
- Smith came mostly unstuck in uneven contest
- Male is lighter in unfair sporting contest
- Incompatible couple, like a red sock and a blue sock, perhaps
Buddy explains!

The straight part
We know that "unfair sporting contest" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case unfair sporting contest = mismatch.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 MISMATCH mean?
MISMATCH verb- To match unsuitably; to fail to match
- Something that does not match; something dissimilar, inappropriate or unsuitable.