A terrorist is just a freedom fighter by another name. Whether he counts as a hero or a villain depends entirely on your point of view.
There's certainly overlap between 'Terrorist' and 'Freedom fighter'. The Maquis and the Bajoran resistance fall into that overlap.
Pretty hard to describe Terra Firma, The Circle or abortion clinic bombers as 'Freedom fighters'. Terrorists who fight not for freedom, but to force people to follow their own will.