(martial arts) The Japanese martial art that is a collection of techniques originally practiced for Japanese espionage purposes, and includes methods of gathering information, nondetection, avoidance, and misdirection techniques. Used by ninja (忍者).
From Japanese忍術 (ninjutsu にんじゅつ), from Middle Chinese 忍 (nyín "to forbear") + 術 (ʑwit "technique").
English Wiktionary. Available under CC-BY-SA license.