A headbutt is a strike with the head, typically involving the use of robust parts of the cranium as areas of impact. Effective headbutting revolves around striking a sensitive area with a less sensitive area, such as striking the nose of an opponent with the forehead. It is known as a risky maneuver: a misplaced headbutt can cause more damage to the person delivering the headbutt than to the person receiving it.
From French botter = "to kick". Rams are well known for butting with their heads and horns. From this the terms battering ram and hydraulic ram are derived. Many males in various animal species employ butting during courtship.
In the UK, a headbutt is sometimes referred to as a "Glasgow Kiss". This is a tongue-in-cheek reference to the city of Glasgow's violent reputation.
Headbutts can be used from close range such as from the clinch, or on the ground. They are typically applied to the head of the opponent, since the head is often a readily available target and has several sensitive areas. An effective headbutt can be performed with a forward, rising, sideways or backwards motion; each being effective from different positions.
Parts of the cranium with thick bone and high local curvature make for good weapon areas, and these include the forehead near the hairline, the outboard curved part of the parietal bone, and the occiput. Ideal targets are usually the fragile areas of the head, including the bridge of the nose, the cheekbones, the hinge area of the jaw, the temple, and the top edge of the eye socket.
Hitting the opponent's teeth or mouth is likely to cause mutual damage. The chin of the enemy is also a generally bad position to headbutt unless striking from below up into the bottom of the chin, similar to an uppercut.