Diligent American leaving for workshop (6)
I believe the answer is:
studio
'workshop' is the definition.
(thesaurus)
'diligent american leaving' is the wordplay.
'diligent' becomes 'studious' ('studious' can be similar in meaning to 'diligent').
'american' becomes 'us'.
'leaving' suggests deleting specific letters.
'studious' with 'us' taken away is 'STUDIO'.
'for' is the link.
(Other definitions for studio that I've seen before include "Dance practice room" , "Workshop for 27 dn" , "Room designer may get" , "Type of apartment without a separate bedroom" , "Where an artist works" .)