From Wikinormous

Lexical version;

the use of violence and intimidation in the pursuit of political aims

FBI phraseology;

"Terrorism is the unlawful use of force and 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."

So "lawful" will make it morally justifiable? 'Law' is simply one persons/peoples arbitrary way to morally justify the use of 'violence and intimidation', and may be equally 'unlawful' in the eyes of its counterpart. The act should stand clear by its own definition as the lexical version, plainly, 'violence and intimidation' i.e. terrorism. The behind agenda and motives is the real subject matter to dissect.

Ronald Reagan said;

”One man’s terrorist is another man’s freedom fighter.”

Peter Ustinov said (paraphrasing);

Terrorism is military for poor, military is terrorism for rich”