harikari vs seppuku

harikari and seppuku both are nouns.

Word	Noun	Adjective	Verb	Adverb
harikari	Yes	No	No	No
seppuku	Yes	No	No	No

As nouns, harikari and seppuku are synonyms defined as:

harikari and seppuku: ritual suicide by self-disembowelment on a sword; practiced by samurai in the traditional Japanese society

Other synonyms of harikari include hara-kiri, harakiri.

harikari (noun)	seppuku (noun)
ritual suicide by self-disembowelment on a sword; practiced by samurai in the traditional Japanese society	ritual suicide by self-disembowelment on a sword; practiced by samurai in the traditional Japanese society