Foolishly eats in improperly licensed food store (12)
I believe the answer is:
delicatessen
'food store' is the definition.
'foolishly eats in improperly licensed' is the wordplay.
'foolishly' indicates an anagram.
'in' means one lot of letters goes inside another.
'improperly' indicates anagramming the letters (I've seen this in other clues).
'eats' is an anagram of 'ates'.
'licensed' with letters rearranged gives 'delicsen'.
'ates' inserted into 'delicsen' is 'DELICATESSEN'.
(Other definitions for delicatessen that I've seen before include "Rich food had here, perhaps?" , "Shop selling exotic prepared foods" , "Seller of fine foods" , "Unusual foods here" , "Rare food shop" .)