One not turning up to eat? That hurts! (2,4)
I believe the answer is:
no-show
'one not turning up' is the definition.
(I've seen this before)
'eat? that hurts' is the subsidiary indication.
'eat?' becomes 'nosh' (noshing is a kind of eating).
'that hurts' becomes 'ow'.
'nosh'+'ow'='noshow'
'to' is the link.
(Other definitions for no-show that I've seen before include "One who fails to arrive" , "Individual neither using nor cancelling a ticket" , "One not turning up" , "Failure to appear" , "Non-attender" .)