With which writer discovers new lead? (6,9)
I believe the answer is:
pencil sharpener
'new lead?' is the definition.
The definition suggests a singular noun which matches the answer.
'with which writer discovers' is the wordplay.
I cannot quite see how this works, but
'writer' could be 'pencil' (I've seen this before) and 'pencil' is located in the answer.
The remaining letters 'sharpener' is a valid word which might be clued in a way I don't understand.
This may be the basis of clue (or it may be nonsense).
(Other definitions for pencil sharpener that I've seen before include "Desk item" , "It's used to make a point" , "something struggling writer might resort to" , "shaving device" , "that makes lead go further" .)