Product with which a shifty tout admits turning up (6)
I believe the answer is:
output
'product' is the definition.
(output is a kind of product)
'a shifty tout admits turning up' is the wordplay.
'a shifty' indicates an anagram.
'admits' means one lot of letters goes inside another (to admit is to allow in).
'turning' indicates an anagram.
'tout' with letters rearranged gives 'outt'.
'up' is an anagram of 'pu'.
'outt' going around 'pu' is 'OUTPUT'.
'with which' acts as a link.
(Other definitions for output that I've seen before include "Amount produced, yield" , "Yield, end product" , "Amount produced by a worker or machine" , "Production; signal" , "What is produced in a given period" .)