Heart of minister I learnt is clean (7)
I believe the answer is:
sterile
'is clean' is the definition.
(thesaurus)
'heart of minister i learnt' is the wordplay.
'heart of' says the answer is hidden in the clue.
'STERILE' is hidden within 'minister i learnt'.
(Other definitions for sterile that I've seen before include "Fruitless" , "Unproductive" , "Uninspired" , "like a mule" , "Free from bacteria" .)