The most common and most likely answer to this crossword clue is the 8 letter word DETRACTS
I've seen this crossword clue in The Guardian
D
E
T
R
A
C
T
S
Buddy explains!

The straight part
We know that "spoils" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case spoils = detracts.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 DETRACTS mean?
DETRACTS verb- To take away; to withdraw or remove.
- To take credit or reputation from; to defame or decry.