The definition is very relevant, since it gives sanction to the act.
Pearl Harbor was always considered a cowardly act since it was done while the Japanese were still negotiating with us.
Attacking unarmed civilians, who are not even aware they are in a war, is a cowardly act, not a courageous one, as Bill Maher, tried to define it.
I would agree completely as to attacking civilians, it’s cowardly. And imo the 9/11 group were cowards. Just not a point worth arguing. We killed plenty of courageous Japanese, with just cause, that’s the issue. If the 9/11 boys are courageous, kill the next ones anyway. You do have a point relative to the reverence accorded them in the Arab world, but I doubt they’ll be swayed by an FR conversation.