Superior shoe part (5)
I believe the answer is:
upper
I believe this clue is a double definition.
'superior' is the first definition.
(I've seen this before)
'shoe part' is the second definition.
(Other definitions for upper that I've seen before include "Section of Oxford" , "Higher in position; drug" , "Part of shoe above sole" , "Stimulant drug (informal)" , "Higher in place or position" .)