Hara-kiri (Japanese for belly-cutting) is the standard spelling for the Japanese method of suicide involving disembowelment, usually self-inflicted, with a sword. Harakiri and harikari are accepted alternative spellings, but most dictionaries recommend hara-kiri.
Hara-kiri is also known as seppuku. There are some subtle historical and linguistic differences between the two terms (seppuku is formal; hara-kiri is slang), but in English they are synonyms.
Examples
I came to a startling conclusion that I was being set up to commit hara-kiri, a ritual suicide. [Huffington Post]
However, instead of constant complaints, the city should work with the province so this does not become an act of governmental hara-kiri. [Winnipeg Free Press]
Following that was a loud bang, presumably a transformer committing hara-kiri. [WJLA]
