Unproductive part of Leicester, I learnt (7)
I believe the answer is:
sterile
'unproductive' is the definition.
(thesaurus)
'part of leicester i learnt' is the wordplay.
'part of' indicates the answer is hidden within the clue.
'STERILE' is hidden within 'leicester i learnt'.
(Other definitions for sterile that I've seen before include "Like theatre" , "Ineffective" , "Unable to have offspring" , "like a mule" , "Pointless" .)