The whole point of picking a specific target is that you consider them a combatant. (You don't have to shoot a gun to be a combatant, helping the military is enough.) A civilian contractor for the military can be a combatant. So no, the Iranian car bombings would not legally qualify as terrorism under U.S. law - the bombings targeted a combatant.

Intent matters too: Are you are killing a person because of that specific person? (To prevent that person from contributing to the military.) Or are you killing so that other people see the killing and get scared?

You are right that it's a silly argument because your eyes appear to be closed on the matter (although to your credit you argue constructively). So lets turn this around, in your eyes in what scenario would it be assassination and not terrorism?

I don't think there are too many other technological details to be found, so this thread is likely to end up as a huge discussion of the morals of this action.

I can assure you all killings are done with noble intent. It just matters who you ask and or listen to.

As Justice Potter Stewart said in his concurrence in Jacobellis v. Ohio, "I shall not today attempt further to define the kinds of material I understand to be embraced within that shorthand description; and perhaps I could never succeed in intelligibly doing so. But I know it when I see it, and the motion picture involved in this case is not that." (that's his complete concurrence)

The same could be true for terrorism. We know it when we see it. No objective definition necessary, so we will make do with it as a political label.