Killed, perhaps, with a single stroke (4)
I believe the answer is:
shot
I believe this clue is a quadruple definition!!
'killed' is the first definition.
(shooting is a kind of killing)
'perhaps' is the second definition.
(thesaurus)
'with' acts as a link.
'a single' is the third definition.
The definition and answer can be both acts as well as being singular nouns.
Maybe there's an association between them I don't understand?
'stroke' is the fourth definition.
(shot is a kind of stroke)
Can you help me to learn more?
(Other definitions for shot that I've seen before include "pop!" , "Fired; (be) rid (of)" , "Injection" , "Charge" , "Sound of gun" .)