Copper replaces one, making patrol complete (5)
I believe the answer is:
uncut
'complete' is the definition.
(synonyms)
'copper replaces one making patrol' is the wordplay.
I cannot quite see how this works, but
'copper' could be 'cu' (chemical symbol) and 'cu' is located in the answer.
'one' could be 'un' (northern English dialect form of 'one') and 'un' is located in the answer.
A single letter 't' remains which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for uncut that I've seen before include "(Like a book) with pages not trimmed" , "State of raw unprocessed diamond" , "the whole pack" , "Descriptive of raw diamonds" , "Retaining full length" .)