Criticise, feeling last twinge (4)
I believe the answer is:
pang
'twinge' is the definition.
(I know that twinge can be written as pang)
'criticise feeling last' is the wordplay.
'criticise' becomes 'pan' (informal term meaning to criticise heavily).
'last' says to take the final letters.
The last letter of 'feeling' is 'g'.
'pan'+'g'='PANG'
(Other definitions for pang that I've seen before include "Sudden painful emotion" , "Mental pain or distress" , "Sharp pain, of hunger or emotion perhaps" , "Short violent pain" , "Sharp emotional pain" .)