What is the meaning of Ninjutsu?

A 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).

Rōmaji transcription of にんじゅつ

ninjutsu (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)

ninjutsu (Japanese martial art used for espionage)

ninjutsu

Source: wiktionary.org