It is a largely useless term; but if there were an ‘original meaning’ from which it has been divorced, it could always be salvaged just by unleashing a crack team of assault philologists on the problem.
Doing so would probably be interesting in any case; but I suspect that the larger problem is that there simply isn’t some sort of ‘original meaning’ in any but the most trivial “Well, as it so happens, Mr. So-and-So first called his opponent a ‘terrorist’ on date X in publication Y…” sense.
