Manchester, I learn, is somewhat barren (7)
I believe the answer is:
sterile
'barren' is the definition.
(thesaurus)
'manchester i learn is somewhat' is the wordplay.
'is somewhat' indicates the answer is hidden within the clue.
'STERILE' can be found hidden inside 'manchester i learn'.
(Other definitions for sterile that I've seen before include "Lab so clean" , "Not able to produce offspring" , "Non-productive" , "Unable to produce young" , "Like theatre" .)