Sort of restriction of which a despicable fellow has not many (6)
I believe the answer is:
curfew
This clue could be a double definition.
'sort of restriction' is the first definition.
'curfew' can be an answer for 'restriction' (I've seen this before). I am not certain of the 'sort of' bit.
'of which a despicable fellow has not many' is the second definition.
The definition suggests a singular noun which matches the answer.
Can you help me to learn more?
(Other definitions for curfew that I've seen before include "Order prohibiting outside activities after a given time" , "Restriction on being out after dark" , "travel restriction" , "Official order restricting people's movements" , "Early closing time imposed by military" .)