Lecturer stopping scruffy notes being plagiarised (6)
I believe the answer is:
stolen
'being plagiarised' is the definition.
(thesaurus)
'lecturer stopping scruffy notes' is the wordplay.
'lecturer' becomes 'l'.
'stopping' is an insertion indicator (stopping can mean blocking a gap).
'scruffy' indicates an anagram.
'notes' anagrammed gives 'stoen'.
'l' inserted inside 'stoen' is 'STOLEN'.
(Other definitions for stolen that I've seen before include "Snatched" , "Taken by thieves" , "Taken without permission or payment" , "Goods that have been taken dishonestly" , "subject to plagiarism" .)