ninjitsu vs ninjutsu

ninjitsu and ninjutsu both are nouns.

Word	Noun	Adjective	Verb	Adverb
ninjitsu	Yes	No	No	No
ninjutsu	Yes	No	No	No

As nouns, ninjitsu and ninjutsu are synonyms defined as:

ninjitsu and ninjutsu: the traditional Japanese method of espionage; involves stealthy movements and the use of camouflage

ninjitsu (noun)	ninjutsu (noun)
the traditional Japanese method of espionage; involves stealthy movements and the use of camouflage	the traditional Japanese method of espionage; involves stealthy movements and the use of camouflage