Dry piece of oyster I left (7)
I believe the answer is:
sterile
'dry' is the definition.
(thesaurus)
'piece of oyster i left' is the wordplay.
'piece of' indicates the answer is hidden within the clue.
'STERILE' can be found hidden inside 'oyster i left'.
(Other definitions for sterile that I've seen before include "unable to reproduce results" , "Unproductive" , "Non-productive" , "Like theatre" , "Unable to have children" .)