Copper’s in luck, finding stripper (6)
I believe the answer is:
locust
'stripper' is the definition.
(I've seen this before)
'copper's in luck' is the wordplay.
'copper's' becomes 'cus' (chemical symbol).
'in' is an insertion indicator.
'luck' becomes 'lot' ('lot' can be a synonym of 'luck').
'cus' placed within 'lot' is 'LOCUST'.
'finding' is the link.
(Other definitions for locust that I've seen before include "Clouts (anag)" , "Destructive creature" , "Swarming grasshopper" , "Dreaded grasshopper that swarms and devours" , "Destructive insect; tree" .)