As a rogue, he will not do well (5)
I believe the answer is:
scamp
'do well' is the definition.
'scamp' can be an answer for 'do' (scamping is a kind of doing). I'm not certain of the 'well' bit.
'as a rogue he will not' is the wordplay.
I cannot quite see how this works, but
'a' could be 'amp' (A is the symbol for the amp or ampere) and 'amp' is found in the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for scamp that I've seen before include "Troublemaker" , "Rogue - perform inadequately" , "Impish youngster" , "Scoundrel" , "Impish child" .)