The ideogram BU in Japanese, WU in Chinese, MOO (MU) in Korean, VO in Vietnamese... means "Martial" or "War". You find it in the words Bushido, Budo, Wushu, Vodao...  An etymology study, sometimes controversial but at least meaningful, used to say that it is the combination of two keys meaning "to stop" - "the spear, the weapon".
 
 

            This famous sentence means to be both cultured in knowledge and effective in martial arts. Often the ideas of  Wen/Bun/Mun (literary, knowledge / exterior beauty) and Wu/Bu/Mu (martial / interior essence) seems contrary -- mostly in our western countries. And yet, the eastern use often associate those charatcers. In Chinese, refinement, elegance can be felt from this combination. In Japanese, you can find the notion of uruwashii, "balance and harmony between exterior beauty and deep essence" e.g. found in the classical Heike Monogatari. This expression is a good summary of the purpose of every Martial Artists, isn't it ?