https://en.wikipedia.org/wiki/Terrorism
>Terrorism, in its broadest sense, is the use of violence against non-combatants to achieve political or ideological aims.[1] The term is used in this regard primarily to refer to intentional violence during peacetime or in the context of war against non-combatants.[2] There are various different definitions of terrorism, with no universal agreement about it.[3][4][5] Different definitions of terrorism emphasize its randomness, its aim to instill fear, and its broader impact beyond its immediate victims.[1]
>Modern terrorism, evolving from earlier iterations, employs various tactics to pursue political goals, often leveraging fear as a strategic tool to influence decision makers.
There is some debate on the fringes of the definition, but not all state actions are terrorism. For example, if a state military goal is simply to kill or disable your enemy by force, that isnt terrorism. Wars of extermination aren't terrorism either. That said, targeting non-combatants to hurt morale is a pretty common terrorism tactic. You could make a strong case that the bombing the civilians of London, Dresden, or Tokyo were acts of terrorism.
Outside of state militaries, it is pretty hard to imagine a principal that separates Luigi from abortion clinic bombers, The Weather Underground, or other domestic terrorists.