Imported copper: high grade, half mended (8)
I believe the answer is:
gendarme
'imported copper' is the definition.
(a gendarme is a French police officer)
'high grade half mended' is the wordplay.
'high' is an anagram indicator (like drunk).
'half' indicates taking half.
'mended' cut in half is 'men'.
'grade'+'men'='grademen'
'grademen' is an anagram of 'GENDARME'.
(Other definitions for gendarme that I've seen before include "Law enforcer" , "see in Paris!" , "Member of the French police" , "French Connection cop" , "Nice policeman" .)