This Protestant, sir, could be seen as unrighteous (8)
I believe the answer is:
huguenot
'this protestant' is the definition.
(I've seen this before)
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for huguenot that I've seen before include "Persecuted French protestant" , "This French protester" , "French Protestant who may have emigrated to Ireland in 17th century" , "C16-17 French Protestant" , "Historically, a French protestant" .)