To be fair, terrorist and freedom fighter aren’t mutually exclusive, nor is the term terrorist entirely a moral judgement, even if it’s often used that way. In a literal sense it would be someone who uses violence in a way that is primarily intended to cause fear, rather than direct damage, in order to further their political aims. Freedom fighters will often do this kind of thing, because they tend to be in a disadvantaged position where actually causing enough damage to force their opponent to leave is unlikely, but scaring their enemies enough that they might consider staying not to be worth it feels more possible.