The most common and most likely answer to this crossword clue is the 8 letter word OVERWORK
I've seen this crossword clue in The Guardian
O
V
E
R
W
O
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K
More clues leading to the result OVERWORK
Buddy explains!

The straight part
We know that "Exploit" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case exploit = overwork.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 OVERWORK mean?
OVERWORK verb- To make (someone) work too hard.
- To work too hard.
- To fill too full of work; to crowd with labour.
- To decorate all over.
- A superstructure
- Excessive work