Neckwear gives good service to . . . (8)
I believe the answer is:
scarface
'neckwear gives good service to' is the definition.
I can't judge whether this definition defines the answer.
'neckwear gives good service' is the wordplay.
I cannot quite see how this works, but
'neckwear' could be 'scarf' (I've seen this before) and 'scarf' is located in the answer.
'service' could be 'ace' (ace is a kind of service) and 'ace' is located in the answer.
No letters remain.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for scarface that I've seen before include "US gangster" , "Al Capone, or Tony Montana - 'Say hello to my little friend'." , "Al Capone's nickname" , "Film starring Al Pacino" , "So-called gangster" .)