1. A person with an overblown opinion of his abilities who experiences the misfortune of having his true level of ability revealed to his audience, usually while attempting to demonstrate his knowledge or skill.

2. An overly confident person who screws up big time.

The exact origins of this term are not known. Some speculate that the term may first have been coined in reference to a guy who, while playing a cowboy gunslinger like on TV, shot himself in the foot.
Did you hear about John? That hammer jacker shot himself in the foot while showing off his gun slinging "skills" to his friends!
by Franzig Durpy January 1, 2014
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