In the days of sail, naval vessels mounted cannon carefully and purposefully rigged into positions which optimised the effect of their fire. Occasionally, the rigging of these very heavy guns might come loose, and with the vessel pitching about on high seas or during manuever in battle, the results for the ship and crew could prove catastrophic. The term has come to describe a person lacking prudence or insight, whose actions and/or speech jeopardises the safety of people in their proximity or under their authority.
Like a drunken bully, the politician shrugged off his advisors and taunted the insurgent forces operating in the country his armies were attempting to pacify. He had become a LOOSE CANNON.
Apocryphal attribution to isolated denizens of Appalachian Mountains,(Eastern USA) descendants of some of the earliest Scotch-English settlers, who seem to have had some proclivity for naming their children "William" (familiarly "Bill")and some not inconsiderable inclination to incestuous sexual congress. More recently, the term is used to describe any rural resident,especially in the Southern USA and particularly those living in rather rough-hewn conditions, embracing noticably parochial ideologies and a generally hostile attitude.
When the hillbillies moved into the trailer park, they maintained their habits of firing off their revolvers at odd hours and cohabiting with their livestock.
Officially and legally sanctioned form of suicide for cretins.
Illegal and massively dangerous if ridden anywhere near their capacity on public streets, a tremendous waste of expense for the non-suicidal. Insurance companies love them.
Usually, they last about one summer season before they are:
b)a twisted pile of unobtainium.
Wow! That little old lady left-turned in front of that crotchrocket pilot!
Now he's just a streak of strawberry jelly on the asphalt.