The most common and most likely answer to this crossword clue is the 6 letter word RIVALS
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More clues leading to the result RIVALS
Buddy explains!

The straight part
We know that "adversaries" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case adversaries = rivals.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 RIVALS mean?
RIVALS noun- A competitor (person, team, company, etc.) with the same goal as another, or striving to attain the same thing. Defeating a rival may be a primary or necessary goal of a competitor.
- Someone or something with similar claims of quality or distinction as another.
- One having a common right or privilege with another; a partner.
- To oppose or compete with.
- To be equal to, or match, or to surpass another.
- To strive to equal or excel; to emulate.