Not genuine piece of porcelain, since reproduction (9)
I believe the answer is:
insincere
'not genuine' is the definition.
(I've seen this before)
'of porcelain since reproduction' is the wordplay.
'of' indicates the answer is hidden within the clue.
'INSINCERE' is hidden within 'porcelain since reproduction'.
'piece' acts as a link.
(Other definitions for insincere that I've seen before include "displaying hypocrisy" , "Feigned, fawning" , "fake" , "Not genuine, feigned" , "Untruthful" .)