The most common and most likely answer to this crossword clue is the 8 letter word RENEGADE
I've seen this crossword clue in The Times
R
E
N
E
G
A
D
E
More clues leading to the result RENEGADE
- Need gear to move rat
- Study including data about European rat
- Newton, say, engrossed in study, finally forgave dissident
- Rebel Frenchman, by Jove, beginning to excel
- Traitor from the east used a general's clothing
- Rebel in den, eager, properly prepared
- Rebel Frenchman seen with grandee regularly
- Rebel Frenchman for example brought back without notice
- Outlaw’s oath stopping Frenchman
- Turncoat Frenchman? Bloody hell – English!
Buddy explains!
The straight part
We know that "rat" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case rat = renegade.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 RENEGADE mean?
RENEGADE noun- An outlaw or rebel.
- A disloyal person who betrays or deserts a cause, religion, political party, friend, etc.
- To desert one's cause, or change one's loyalties; to commit betrayal.