In boxing/martial arts: a technique done by the foremost bodily weapon (99% of the time, the foremost fist). The strike is linear and the power is not the best stopping technique due to limited displacement of weight in the time executed. It is often a "
feeler" technique designed to 'stun', or 'follow up' with another technique (usually the cross-punch).
More power can be mustered with the strike if the hips are
stabilized, the shoulders displaced forwards, and the feet grounded from their footwork. This is subject to the art and the user, but a jab can muster more of the body than simply
the arm's extension and muscle.
A jab can also be a foot strike with the frontal foot in a
sideways stance that "pokes" at the opponent with the intent of fending them off, or causing "stunning" pain to the shin, groin, abdomen, or higher targets. This "foot fencing" is designed to follow up with another technique or to buy time.