Well definitely not number 4. I don't see how open derision would help any kind of dialogue in any way ever. I guess for me, the nontrivial meaning would be someone who has terror not as an adventitious effect of their goal, i.e. conquering Europe, but as a major objective. Ends vs means, I suppose. I definitely think "terrorist" is being used to manipulate people, but so is pretty much every other important term ever. We could get technical about the etymology and the technical meaning of the word "tyrant," and how it has more to do with hereditary legitimacy than actual treatment, but the word has evolved, as all words do, and now it has a lot of connotations that we accept when e use the word in a modern sense.
And whether it's strictly technical or not, the term should still be used so long as someone finds it as a useful shorthand for a larger set of characteristics. Bananas aren't technically fruit, but if you call it one, I get what you mean, and I'm not going to openly deride you unless I'm trying to win a douchebag award.
Which I am. They're not fruits, you losers! Bwahaha!