>>4 Terrorism has more to do with motive than action. No combination of other law terms really quite cover it.
Terrorism is any act carried out with the purpose to incite terror. Most commonly, this refers to mass murder of civilians. The ultimate goal is not necessarily the killing itself, but the fear and panic it creates.
For example, take the American Revolution. Certainly, the revolutionaries obtained weapons illegally, committed treason, and murdered and intimidated countless British troops. However, I think few would suggest this is terrorism because the goal of the Revolution, ultimately, was to obtain freedom, not to terrify the British peoples.
While the term 'terrorism' is arguably misused by government agents in order to circumvent legal process, I'd like to note that the term is still valid, even if its application isn't.