jump the gun

to do something too soon, especially without thinking carefully about it (Originally used in sports contests that are started by firing a gun. If someone running in a race jumps the gun, they start running before the gun has been fired to start the race.)
On this page, you will find 30 slang terms related to jump the gun. Some of the top words include: jump the gun, super bike!, book, mind fuck, book it, and 25 more.