The most common and most likely answer to this crossword clue is the 9 letter word DISSIDENT
I've seen this crossword clue in The Times
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More clues leading to the result DISSIDENT
- Democrat insisted on change — not one to toe the party line
- Involved in non-conformism, I would ... be this?
- Criticise position on books in opposition to official policy
- Duke isn’t accepting insolence from a government opponent
- Rebel Democrat insisted on change?
- Protester from Germany isn’t welcoming party
- Protester in Norfolk town I injure with punch?
- One opposing official policy — leader of Democrats insisted upon change
- Policeman’s dispatched to check identity for protester
- Policemen flank exterior of nearest protestor
Buddy explains!

The straight part
We know that "this" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case this = dissident.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 DISSIDENT mean?
DISSIDENT noun- A person who formally opposes the current political structure, the political group in power, the policies of the political group in power, or current laws.
- One who disagrees or dissents; one who separates from the established religion.
- In a manner that disagrees; dissenting; discordant.