Terrorize = verb
Terrorism = noun
Ok - that is hereby committed to memory.
Says you. My guess is that you don't have a lot of nits left in your house...
Anyways, here are a couple....
State Department definition, Title 22 of the U.S. Code, Chapter 38, Section 2656f(d)(2): "Premeditated, politically motivated violence perpetrated against non-combatant targets by subnational groups or clandestine agents."
FBI definition: "the unlawful use of force or violence against persons or property to intimidate or coerce a government, the civilian population, or any segment thereof, in furtherance of political or social objectives."
Defense Department definition: "The unlawful use of violence or threat of violence to instill fear and coerce governments or societies. Terrorism is often motivated by religious, political, or other ideological beliefs and committed in the pursuit of goals that are usually political."
Boaz Ganor's (Executive Director of the International Policy Institute for Counter-Terrorism) definition: "the intentional use of, or threat to use violence against civilians or against civilian targets, in order to attain political aims."
Tal Becker, former legal advisor to the Israeli Mission to the UN, affirms "If we define terrorism not by what one does, but what one does it for, we legitimate the deliberate targeting of civilians for certain causes."
Noam Chomsky, American linguist and political critic, adopted his definition from a U.S. Army Manual: "the calculated use of violence or threat of violence to attain goals that are political, religious, or ideological in nature...through intimidation, coercion, or instilling fear.
United Nations Definition: "...any act intended to cause death or serious bodily injury to a civilian, or to any other person not taking an active part in the hostilities in a situation of armed conflict, when the purpose of such act, by its nature or context, is to intimidate a population, or to compel a government or an international organization to do or to abstain from doing any act."
The one that gives the broadest definition, and also the one that makes the most sense logically, is the UN definition. It is not limited to "political purposes", but covers terrorism for any purpose.
The reason why this makes sense is, that having a different punishment for homicide committed for political purposes compared to a robbery or a spree killing is neither fair nor practical. Terrorism is an "act"... a "method" if you will... and the reason why you resort to using this method is irrelevant. The damage done is the same whether you are politically motivated or just an ass.