Shop needs elastic pants? (12)
I believe the answer is:
delicatessen
'shop' is the definition.
(delicatessen is a kind of shop)
'needs elastic pants?' is the wordplay.
'pants?' indicates anagramming the letters (UK informal term for 'nonsense' or 'rubbish').
'needs'+'elastic'='needselastic'
'needselastic' anagrammed gives 'DELICATESSEN'.
(Other definitions for delicatessen that I've seen before include "Fine foods shop" , "Seller of fine foods" , "Rare food shop" , "Shop selling unusual or foreign prepared food" , "food store?" .)