Is the saying head butt or head bunt?

The phrase is 'head butt', but my wife said bunt and it annoys me.

It is important to say that 'head butting' can cause considerable injury! It can cause a broken nose, skull fracture, concussion, brain injury, or even sudden death (also known as a "one punch death"). Head butting should be left to animals who use it to communicate authority and alpha status, as well as a 'greeting', since animals rarely break each others skulls or cause injury or death!

Again, 'head butting' is a form of immature aggression in humans and can cause considerable injury or death! NO ONE should head butt another person!