Consider a scenario where a person is forced to act and attack a person who they consider to be a threat even though there has been no display of such threat. I am talking about sensing danger and acting upon it.
This doesn't sound like self-defence. As usually, self defence is the use of physical force to counter an immediate threat of violence. OxfordDictionaries.com defines it as:
the defence of one’s person or interests, especially through the use of physical force, which is permitted in certain cases as an answer to a charge of violent crime.
I am looking for a word or phrase that would describe an act of premeditated self-defence, in anticipation of a threat.