GIVE ANSWERS - English

To do/say something before getting full information.

Example: He jumped the gun by stating that John was guilty, even before the full evidence was presented at the court.

Long answer to a short, but complex, question:

Literally, the phrase is derived from track & field events like "sprints" and other foot racing events that "commence" at the firing of a "starting gun", when one (or more of) the race's participants "start running" before the sound of the starting gun is fired. Thus, one "jumps the gun", ir, takes off before the official start of the race.

So, in the greater sens, the phrase/expression is used to describe situations where activities, events, or such abstract notions as passing laws or putting technology into operation BEFORE the time is "right", before the said technological device, idea, event, is fully operational and therefore ready for (fully functional) operation.

A good example from Technological devices is the Boeing 737 Max, a newly developed aircraft that was released to the public (ie, airline purchase and use) BEFORE it was determined that the aircraft was fully functional, which later evidence (accidents, other failures) suggest that the Boeing 737 Max WAS NOT READY for general operation.

The upshot: do, start, think, launch, initiate, etc., some phenomenon BEFORE it's ramifications/operational elements have been fully tested/explored and/or has been officially (formally) sanctioned to start operation or commence.