WordNet
n. confusion resulting from lack of preparation
Wikipedia
Half-cock is when the position of the hammer of a firearm is partially—but not completely—cocked. Many firearms, particularly older firearms, had a notch cut into the hammer allowing half-cock, as this position would neither allow the gun to fire nor permit the hammer-mounted firing pin to rest on a live percussion cap or cartridge. The purpose of the half-cock position has variously been used either for loading a firearm, as a safety mechanism, or for both reasons. The still commonly used English expression of "going off half-cocked" derives from the failure of the half-cock mechanism to keep the hammer from falling and the subsequent failure to prevent a firearm from firing when unintended.
Usage examples of "half-cock".
Did you have to race back there half-cocked because you found Karri and me in bed together?
For all his decisiveness, though, he wasn't a cowboy who was likely to endanger people by going off half-cocked.
She used the folds of her sheepskin coat to muffle the click as she drew back the hammer to half-cock.
A silly situation comedy was playing, one of those in which the wife is always an utter lamebrain and the husband continually misunderstands everything he hears and runs around half-cocked, messing up the situation even more than it was before he tried to fix it.