Some in glasshouse definitely exploited (4)
I believe the answer is:
used
'exploited' is the definition.
(synonyms)
'some in glasshouse definitely' is the wordplay.
'some in' indicates the answer is hidden within the clue.
'USED' is hidden in the letters of 'glasshouse definitely'.
(Other definitions for used that I've seen before include "Sued (anag.)" , "cast off" , "not got directly" , "worked unfairly" , "Utilised" .)