Anyone leaving A&E without left stocking? (5)
I believe the answer is:
nylon
'stocking?' is the definition.
(nylon stocking is a kind of stocking)
'anyone leaving ae without left' is the wordplay.
'leaving' indicates named letters should be taken away.
'without' means one lot of letters goes inside another ('without' can be similar in meaning to 'outside').
'left' becomes 'l' (common abbreviation).
'anyone' with 'ae' taken away is 'nyon'.
'nyon' enclosing 'l' is 'NYLON'.
(Other definitions for nylon that I've seen before include "where ladder can appear?" , "may be damaged by running" , "Type of material" , "Plastic used for stockings" , "Tights material" .)