seppuku vs harikari

seppuku and harikari both are nouns.

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

As nouns, seppuku and harikari are synonyms defined as:

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

Other synonyms of seppuku include hara-kiri, harakiri.

seppuku (noun)	harikari (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