Wars are by definition lawful. Sorry you’re wrong
It’s also not a twisted definition. It’s the literal dictionary definition that all countries use when defining terrorism.
And no, if war time acts were not lawful, all war is terrorism which it isn’t so again you’re wrong.
War crimes are explicitly not terrorism by definition. If you need a basic high school education though there’s hopefully a public school near you. This subject and topic is covered under civics.