Needs to get hot food (4)
I believe the answer is:
'food' is the definition.
(hash is a kind of food)
'needs to get hot' is the wordplay.
'needs' becomes 'has' ('have' can be a synonym of 'need').
'to get' is a charade indicator (letters next to each other).
'hot' becomes 'h' (abbreviation eg on taps).
'has'+'h'='HASH'
(Other definitions for hash that I've seen before include "meat and potato dish" , "Recooked dish for shah" , "Meat dish; mess, jumble" , "Recooked dish - quite a jumble" , "Minced meat and vegetables - a mess!" .)