by this definition, lots of US soldiers are terrorists, they kill (sometimes intentionally, sometimes not, sometimes forcedly) civilians in Libya, Iraq (where nuclear weapon not found), Syria, Vietnam in old days and in many more countries

> Taleban attacking a military base are not terrorists by that definition

Of course, they are defending their own place, what the hell is military base of different country is doing something in totally different country, maybe occupation? which means using terroristic acts

It's this kind of sloppy thinking that makes a rational discussion of this topic (and many other controversial topics) so hard. I wrote "intentionally target noncombatant civilians" and you essentially ignored this.

There is a huge difference whether you kill someone intentionally or non-intentionally as a side effect, or at least that's what the majority of people who seriously think about this topic agree upon. Intentional killings of noncombatant civilians by US army members are considered crimes or war crime, depending on the circumstances. They are often prosecuted. But I've already mentioned legal grey zones such as drone strikes in which the killing of innocent bystanders is not intended but taken into account.

> Of course, they [the Taleban] are defending their own place,

But they are often classified as terrorists, hence the example. Just to make this clear as well, the example is a bit ill-conceived in retrospective, since there is no doubt that Taleban as an organization are terrorists - they bomb cilivians in cities all the time. Of course, the definition of a terrorist organization is more complicated than just "they always intentionally kill civilians".