A leader perhaps but he won't lead (6)
I believe the answer is:
dealer
'he won't lead' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'a leader perhaps' is the wordplay.
'perhaps' is an anagram indicator.
'leader' is an anagram of 'DEALER'.
'but' is the link.
Can you help me to learn more?
(Other definitions for dealer that I've seen before include "Trader as on Stock Exchange" , "Trader; card player" , "One gives out the cards" , "Stockjobber" , "putting his cards on the table?" .)