Can we define terrorism when one mans freedom fighter is another mans terrorist? There is no moral relativity on this at all: A terrorist targets non-combatant civilians to achieve a political goal. Those who undertake political actions that target civilians are terrorists.
Those, for example, who wage an armed struggle on behalf of the oppressed and do so confining their combat to military objectives can be called freedom fighters. The distinction is very clear, and depends on whom you attack.
Read it all. (Hat tip: Hawk Girl).
By this definition, the Contras, much beloved by Right Wing Reaganites, were terrorists.