He attacks the copper with acid (6)
I believe the answer is:
etcher
'he attacks the copper with acid' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'he attacks the' is the wordplay.
I cannot quite understand how this works, but
'he' could be 'che' and 'che' is located in the answer.
'the' could be 't' (the is pronounced as a 't' sound in some dialects) and 't' is found within the answer.
The remaining letters 'er' is a valid word which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for etcher that I've seen before include "Artist using acid on metal" , "One with incisive career" , "Cutter" , "Engraver" , "A designing individual" .)