the.com/ninja

means A covert agent of feudal Japan trained in stealth, infiltration, and irregular tactics — and by extension, anyone who gets things done unseen and unbeatably well.

from From Japanese nin (忍), meaning to endure or stay hidden, plus sha/ja (者), meaning person — literally 'one who endures in secret.' The art itself, ninjutsu, grew out of medieval Japan's need for spies and saboteurs who worked outside samurai codes of open combat. The word barely existed in English until the 20th century, when postwar pop culture — movies, comics, then cartoons — exported 'ninja' worldwide, turning a shadowy historical role into a global shorthand for silent, superhuman competence.