Loose Cannon

Etymology:

• Many years ago, in days when sailors go on board warship, it is noticing that more than enemy of war, they had to be more careful of the cannons that lied on ships. Though these were tied tightly, but if the weather was stormy, then there was a chance for these cannons to get loose and slid across the slimy floor as the ship gets jolted and tossed here and there, so it could crashed into things or people on the ship causing great damage. Today a person can be called a “loose cannon” that is short tempered and have wild behavior.