The most common and most likely answer to this crossword clue is the 2 plus 3 plus 3 plus 2 plus 3 letter word AN EYE FOR AN EYE
I've seen this crossword clue in The Daily Telegraph
A
N
E
Y
E
F
O
R
A
N
E
Y
E
More clues leading to the result AN EYE FOR AN EYE
Buddy explains!
The straight part
We know that "A fair exchange in sight?" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case a fair exchange in sight? = an eye for an eye.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.