Can the 1945 nuclear bombings be considered as terrorist attacks?

No, they were carried out during a war by a recognized nation. To be qualified as a terrorist act the bombers would have done that during peacetime and not have a nation behind them.

Which is why the bombing of Pearl Harbor, while we were not at war with Japan isn't a terrorist act, but an act of war. Japan is a nation.

WW2 was an all-out war to the death and only the nuclear bombs brought it to a swift ending.

During WWII it was expected that the enemy would attck the civilian infrastructure as well as the general population. By the way they were ATOMIC bombs, not Nuclear. Big difference.

Sure lib, then any bombing in history would be a terrorist act. Do you think conventional bombs are discriminate??

Typically any bomb used to target a terrorist or enemy takes out civilians.

By modern definition it could potentially be considered a war crime.

The counter argument is that it SAVED many, many more lives by forcing japan to surrender (and despite japan obviously losing the war, surrender wasn't considered until after the bombs were dropped, and even then it took 2).

By modern definition, I think they would be considered as massacres...

「テロ」ではなく「(国家による)大量虐殺」になると思います。

There was a war on, nitwit. It was called World War II. Look it up.