We don't have synonyms for ninjitsu yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are jiujitsu, ninjutsu and ningirsu.
(n) :
Alternative form of ninjutsu. [(martial arts) 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).]
(n) :
Alternative form of ninjutsu. [(martial arts) 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).]