Artist, for instance, in sad disarray (5)
I believe the answer is:
degas
'artist' is the definition.
(painter Edgar Degas)
'for instance in sad disarray' is the wordplay.
'for instance' becomes 'eg' (short for 'exempli gratia', 'for example' in Latin).
'in' means one lot of letters goes inside another.
'disarray' indicates anagramming the letters.
'sad' with letters rearranged gives 'das'.
'eg' placed within 'das' is 'DEGAS'.
(Other definitions for degas that I've seen before include "Edgar -, Fr. artist" , "French impressionist painter, d. 1917" , "He produced works of art" , "French artist known for his ballet scenes, d.1917" , "Edgar -, Fr. sculptor/ painter" .)