Definition of overkilling:
(n) :
(by extension) An unnecessary excess of whatever is needed to achieve a goal.
(v) :
To do something excessive to achieve a goal.
(n) :
(literally, military) A destructive capacity that exceeds that needed to destroy an enemy; especially with nuclear weapons.
(n) :
(literally) Destruction beyond what is necessary to kill, especially in murder.
(v) :
(transitive) To destroy something with more (nuclear) force than is required.
(n) :
(manufacturing) An unnecessary excess of disposal because of too high criteria of inspection.