Eta have no support from the people they are trying to liberate.
Their methods of indiscriminate killings and bombings, kidnappings and extorsion of money from Basque industralists, money claimed to be for helping a cause they dont believe in, thus obliging them to cooperate or suffer retribution. Is that enough to call them terrorists?
My definition of terrorism is more or less what you said, inflicting pain intentionally on civilians, yet my point here was to argue that the situation of ETA differs from that of the PLO. The PLO enjoys support to the extent in which one must question the notion of a terrorist population, in so far as they applaud the actions taken by said groups, as they believe it to be a necessity, in terms of warfare and of retribution. As one of Hamas leaders said: If a Palestinian mother cries, then a jewish mother must cry too