He doesn't give his customers socks! (6)
I believe the answer is:
hosier
'doesn't give his customers socks' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'he' is the wordplay.
I cannot quite see how this works, but
'he' could be 'si' and 'si' is found within the answer.
The remaining letters 'hoer' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for hosier that I've seen before include "Dealer in socks and stockings" , "Shopkeeper who sells stockings" , "One sells socks and stockings" , "Maker or dealer in stockings" , "Manufacturer or seller of stockings" .)