Exhausted artist had dinner outside (7)
I believe the answer is:
drained
'exhausted' is the definition.
(draining is a kind of exhausting)
'artist had dinner outside' is the wordplay.
'artist' becomes 'ra' (Royal Academician, member of Royal Academy of Arts).
'had dinner' becomes 'dined' ('dine' can be a synonym of 'have dinner').
'outside' means one lot of letters goes inside another.
'ra' put within 'dined' is 'DRAINED'.
(Other definitions for drained that I've seen before include "empty" , "Tired" , "Deprived of strength" , "spent" , "Emptied of liquid" .)