This skill is almost impossible to learn.
The skill is automatically in use.
Blunt weapons are heavy, slow and require practising and experience. You could always pick up just about any stick or long piece of wood and start messing around, but without this skill, you do not get great results and likely manage only get yourself killed quickly as well. This skill determines your skill with blunt weapons, weapons that were the first ones invented by every culture in ancient times of development of different races. One should not underestimate these weapons, as a skilled warrior in this can cause devastating damage.