Food shop back next to King's Cross (5)
I believe the answer is:
riled
'cross' is the definition.
(I've seen this before)
'food shop back next to king's' is the wordplay.
'food shop' becomes 'deli' (short for delicatessen).
'back' says the letters should be written backwards.
'next to' is a charade indicator (letters next to each other).
'king' becomes 'R' (abbreviation for rex, king in Latin).
'deli' backwards is 'iled'.
'iled' after 'r' is 'RILED'.
(Other definitions for riled that I've seen before include "get angry" , "Irritated, provoked" , "Made angry" , "Nettled" , "Cross" .)