Like some piece judged to be plagiarised (7)
I believe the answer is:
pirated
'be plagiarised' is the definition.
(thesaurus)
'like some piece judged' is the wordplay.
'like some piece' becomes 'pi' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'judged' becomes 'rated' (rating is a kind of judging).
'pi'+'rated'='PIRATED'
'to' is the link.
Can you help me to learn more?
(Other definitions for pirated that I've seen before include "Used in defiance of copyright" , "knocked off" , "Published without permission" , "Copied" .)