"suicide by disembowelment," 1856, from Japanese, "belly-cutting," the colloquial word for what is formally called seppuku "cut open the stomach," from hara "belly" + kiri "to cut."
c.1600, from dis- + embowel. Earlier form was disbowel (mid-15c.); embowel, with the same meaning, is attested from 1520s. Related: Disemboweled; disembowelment.