Shinobi was one of the many names given to the
ninja in feudal
Japan. It literally means "stealer-in" because that is what the ninja specialised in above all else - going unnoticed. By employing any number of tricks such as
stealth walking and staying upwind of any
guard animals, the shinobi went undetected about his mission. On a more devious level, the shinobi was also a master of
disguise, and would often "steal in" to village communities disguised as a
local, or even into enemy palaces, disguised as a wandering
priest looking for somewhere to stay
overnight.
However the ninja decided to best go about their missions, they truly lived up to the name shinobi. They were experts finely honed in the art of completing a mission with nobody even knowing they were there.