Master traitor in French history! (5)
I believe the answer is:
marat
'french history' is the definition.
The definition suggests a singular noun which matches the answer.
'master traitor' is the wordplay.
'master' becomes 'ma'.
'traitor' becomes 'rat' (I've seen this before).
'ma'+'rat'='MARAT'
'in' acts as a link.
Can you help me to learn more?
(Other definitions for marat that I've seen before include "Jean Paul -, assassinated French revolutionary" , "Charlotte Corday victim" , "murdered radical" , "revolutionary stabbed" , "French revolutionary killed in his bath" .)