To restate: We see a difference between _____terrorism that targets civilians(read the rest of the thread for the nuances) and _____terrorism that does not.
The FBI definition does not address the difference. We want to.
Here's the problem: to a terrorist, there is no such thing as an innocent bystander -- no such thing as civilians. We can make up our own words to differentiate between civilian killing terrorists and non-civilian killing terrorists, but the definition wouldn't have much of a real-world application. (Furthermore, who are you trying to differentiate between, anyway? What terrorist groups haven't killed civilians?)(And I'm hoping one of you tries to use American revolutionaries as an example, so I can make fun of you.)
However, if you don't like the FBI definition, try one of these. FBI suits my tastes best, but it's certainly not the only definition out there. Looking at these, I think you'd like the state department version best:
State Department definition: premeditated, politically motivated violence perpetrated against noncombatant targets by subnational groups or clandestine agents, usually intended to influence an audience.
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 calculated use, or threatened use, of force or violence against individuals or property to coerce or intimidate governments or societies, often to achieve political, religious, or ideological objectives.
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.