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Someone who has the propensity to act unpredictably or to lose their temper very quickly. You really have to be mindful of what you say to Jake. He's a loose cannon, and the smallest things will send him into a fit of rage. The star quarterback's reputation as a loose cannon hurt his chances of being signed by a new team.
Troops that are deemed expendable and thus given the most dangerous assignments (in which they are likely to be killed by artillery fire). I refuse to be sent to the front lines as cannon fodder!
See also: cannon
a person whose actions are unpredictable and uncontrollable. As it turned out, he's not just a loose cannon. He makes sense. Some loose cannon in the State Department has been leaking stories to the press.
One who is uncontrolled and therefore a serious and unpredictable danger. For example, We can't trust her to talk to the press-she's a loose cannon. This metaphoric expression alludes to cannon mounted on the deck of a sailing ship, which if dislodged during combat or a storm could cause serious damage to both vessel and crew by sliding about. Its figurative use dates from the first half of the 1900s.
1. You call soldiers in a war cannon fodder when they are considered unimportant and are sent to fight in the most dangerous areas, where they are likely to be killed. The 55- to 65-year-olds were sent to the front as cannon-fodder. If you're a squaddie, you're regarded as cannon fodder.
2. You call people cannon fodder when they are made to do difficult, unpleasant, or dangerous tasks that their bosses do not want to do. The average member of parliament would change parties without hesitation, and is treated by his party leaders as cannon fodder. Note: Fodder is cheap food such as hay or straw that is used to feed animals.
See also: cannon
a loose cannon
COMMON If you call someone a loose cannon, you mean that their behaviour is unpredictable and could cause problems. He was also getting a reputation for being a loose cannon; an accident waiting to happen. Thomson can be a loose cannon — he's not easy to control. Note: This expression refers to the cannons which used to be carried on the decks of warships. If one of the cannons was not properly fastened down, it could spin round and make a hole in the ship.
n. a gun; a revolver. (Underworld.) Rocko pulled out his cannon and aimed it at Marlowe’s throat.
n. a device used in the smoking of cannabis. (see also shotgun.) Don had a hash cannon in his office as a sample of a device for smoking pot.
n. a loudmouth; a braggart. As it turned out, he’s not just a loose cannon. He makes sense.