Shinobi, Kunoichi, Ninja

The word ninja became popular in the post-World War II culture. The nin of ninjutsu is the same as that in ninja, whereas jutsu (術) means skill or art, so ninjutsu means "the skill of going unperceived" or "the art of stealth"; hence, ninja and shinobi-no-mono (as well as shinobi) may be translated as "one skilled in the art of stealth." Similarly, the pre-war word ninjutsu-zukai means "one who uses the art of remaining unperceived."