go off at half-cock

go off at half-cock

1. To act hastily or impulsively. I'll admit that I went off at half-cock when I sent that angry email before finding out what really happened.
2. To fail. If the caterer quits, this party is definitely going to go off at half-cock.
See also: go, off

go off half-cocked

To act prematurely, impulsively, or rashly. Don't go off half-cocked and say something you'll regret later.
See also: go, off
Farlex Dictionary of Idioms.

go off half-cocked

Fig. to go into action too early or without thinking. (Originally refers to a flintlock or matchlock gun firing prematurely, before the trigger was pulled.) Don't go off half-cocked. Plan out what you're going to do. Bill went off half-cocked and told everybody he was running for the state legislature.
See also: go, off
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs.

go off at half-cock

BRITISH or

go off half-cocked

mainly AMERICAN
1. If someone goes off at half-cock, they suddenly start doing something without preparing for it or thinking about it enough. She was a disaster in meetings, never preparing and often going off at half-cock. Remember, don't go off half-cocked when we get there. Stick to the plan.
2. If an event or action goes off at half-cock, it is unsuccessful. The organisation had emerged well from an event that many had expected to go off at half-cock. Note: Half-cocked and half-cock can also be used before a noun to describe something that is done badly and not thoroughly enough. Finally there is the matter of the half-cock privatisation of London Underground. In-store guest appearances are usually embarrassing, half-cocked events. Note: If a gun goes off at half-cock, it does not fire properly and so the shot is wasted. This is because the firing mechanism has not been raised high enough to connect with the trigger.
See also: go, off
Collins COBUILD Idioms Dictionary, 3rd ed.

go off at ˌhalf-ˈcock

(informal) start without enough preparation, so that the effect or result is not satisfactory: Let’s not go off at half-cock. We must get enough people together before we start the meeting.This refers to an old type of gun. It it was at half-cock, the firing lever (= cock) was not pulled all the way back so that the gun was not completely ready to fire.
See also: go, off
Farlex Partner Idioms Dictionary

go off half-cocked

in. to proceed without knowing all the facts. The boss went off half-cocked and exploded into a rage about the mess.
See also: go, off
McGraw-Hill's Dictionary of American Slang and Colloquial Expressions

go off at half-cock/half-cocked, to

To act prematurely. The term comes from about 1700, when the hammer of a firearm could be set halfway between the firing and retracted positions. This setting was supposedly secure, but occasionally it slipped and the gun would go off unexpectedly. The term soon was transferred to other occasions when something was done prematurely, especially in the United States. The OED cites an appearance in the 1833 Debates of Congress: “The gentleman from Maryland has gone off half-cocked.”
See also: go, off
The Dictionary of Clichés by Christine Ammer
See also:
  • go off at half-cock/half-cocked, to
  • go off half-cocked
  • at half cock
  • undone
  • what is done cannot be undone
  • what's done cannot be undone
  • cock socket
  • cocksocket
  • cock a
  • cock a snook at somebody/something