Copper's suggested faster route (5,3)
I believe the answer is:
short cut
'faster route' is the definition.
(I've seen this before)
'copper's suggested' is the wordplay.
I cannot really see how this works, but
'copper' could be 'cu' (chemical symbol) and 'cu' is present in the answer.
This may be the basis of clue (or it may be nonsense).
(Other definitions for short cut that I've seen before include "Faster route" , "Time-saving route" , "F key?" , "rat run?" , "Time- or distance-saving route" .)