If you right-click the mouse and then quickly left-click, the punch sound will play, but the punch animation will not.

With bare hands, the sound is played first, and after a delay of about 0.1 seconds, the punch animation is played.
If you have an item, only the sound will play, not the animation.

Also, if you hold some sword and face the ground and perform the same operation, only the animation will be played and the sound will not be played.