Here is the definition:
by Christopher Caile
Bu: (Jap) Military or related to the military . A character often compounded into others such as bugei, bujitsu and bushi. The character for Bu is a composite of two others. The bottom inside left character is foot suggesting advancing on foot, and the right upper larger character is a prototype of a halberd (a type of lance) implying to cut, menace, pierce or kill. When combined they can be interpreted as advancing on foot with a weapon for potential use, thus referring to a warrior or by extension things military. There is also an important secondary interpretation. The first character meaning foot has also come to mean stop, based on the idea of planting the foot. Taken in conjunction with the second character of halberd, "bu" can be thus interpreted as a means to stop a weapon (conflict), or to gain peace. This is consistent with the idea of practicing budo to achieve both inner and outer peace.
Jitsu: (J) (also spelled Jutsu) Method, truth, art of technique. A term used to classify by category those Japanese pre-1600 fighting disciplines, as Kenjitsu (the art or technique of the sword), or sub-category or specialization as iaijitsu (art or technique of sword drawing) whose principal focus was the development and perfection of effective combat techniques used to kill other professional warriors. Jitsu also implies the application and strategy employed by these methods. The actual schools (Ryu) or methods that taught these arts (under collective terms such as kenjitsu) generally used names based on their founder, lineage, philosophy or method.