Good deed during a knife attack (4)
I believe the answer is:
feat
'good deed' is the definition.
'feat' can be an answer for 'deed' (synonyms). I'm not certain of the 'good' bit.
'during a knife attack' is the wordplay.
'during' indicates the answer is hidden within the clue.
'FEAT' is hidden within 'a knife attack'.
Can you help me to learn more?
(Other definitions for feat that I've seen before include "Significant achievement" , "Deed; achievement" , "Great deed" , "Achievement needing great courage or skill" , "An accomplishment of fate" .)