Ok, ok, I have to play Devil's Advocate, here. Let's say a gunman walks into a bank and shoots people. He is armed, correct? Now, the security guard throws down his donut and tackles him to the floor. The gun goes sliding under the dress of a woman asleep in the waiting area. The man under the security guard on the floor is still the gunman, correct? He is now unarmed, correct? :)
HaaHaHa, I too was thinking that there are cases where a gunman doesn't have to be armed. But I didn't think anybody would call me on it.
...also, definition #2 in my Websters says a gunman is a "person who makes guns". So a gunsmith on his lunch hour could also be an unarmed gunman ;)