The most common and most likely answer to this crossword clue is the 6 letter word REBELS
I've seen this crossword clue in The Guardian
R
E
B
E
L
S
More clues leading to the result REBELS
Buddy explains!

The straight part
We know that "Dissenters" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case dissenters = rebels.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 REBELS mean?
REBELS noun- A person who resists an established authority, often violently
- A person from the Confederate States of America
- To resist or become defiant toward an authority.