Perhaps skinny superhero's clothing falls off in the middle of deli (9)
I believe the answer is:
epidermal
'perhaps skinny' is the definition.
(relating to the epidermis, part of the skin)
'superhero's clothing falls off in the middle of deli' is the wordplay.
'superhero' becomes 'Spider-Man' (comic book superhero).
'clothing falls off' says to take the centre (the letters clothing the word are removed).
'in the' indicates putting letters inside.
'middle of' means to look at the middle letters.
The central letters of 'spiderman' are 'piderma'.
The centre of 'deli' is 'el'.
'piderma' inserted into 'el' is 'EPIDERMAL'.
(Other definitions for epidermal that I've seen before include "Like protective covering" , "Like skin" , "Relating to skin surface" , "Of the outer skin" .)