General usage of the word does matter. People who self identify as antifa tend to use violence only in retaliation to violence committed by others or in defense of self or others. The average person wouldn't consider that terrorism. If we care only about the strict websters definition, it becomes difficult to differentiate between any national army and terrorism. What with the violence against civilians for political ends...

I would say that the difference between a national army and terrorism is in the definition.

the unlawful use of violence and intimidation, especially against civilians, in the pursuit of political aims.

In this case, nazis in Germany would not have been terrorists. The French resistance would have been.

There is no moral component in the definition. Once we define a terrorist, we can move on to the discussion of whether the terrorism is morally justified.

I understand that language shifts, but we rely on shared language to communicate. The dictionary definition provides this.

In the initial post you said "I responded that they use violence against civilians for political aims. By definition, they are terrorists". This definition would, in fact, describe some members of antifa as well as nearly every military force in history.

When that was noted, you offered the following definition:

"the unlawful use of violence and intimidation, especially against civilians, in the pursuit of political aims."

This one would exclude military action in most, but not all cases. It also excludes (the american version of) antifa, as using violence in defense of self or others in not unlawful. You can hit someone to make them stop hitting someone else.

I think this kind of proves my point about having accurate shared definitions when discussing things. The second post contains the actual dictionary definition. My first post was from memory. I had posted the full definition on twitter.

I don?t think it excludes Antifa. In some cases they are defending against actual violence, but in others they aren?t. While the majority of Antifa do not take part themselves, they defend the use of violence from the more extreme anarchist members.

The particular twitter conversation contained a side-thread about ?milkshaking?. The defenders were claiming that it didn?t constitute violence or assault. I again rely on Webster?s.

Assault: make a physical attack on.
Violence :the use of physical force so as to injure, abuse, damage, or destroy.

I?m not sure if ?milkshaking? has ever been used in self defense against a physical threat. It HAS been used against people who were speaking in a way that Antifa members disapproved of.