Definition from Wiktionary, the free dictionary
1595, self- + slaughter, possibly taken as a shortening of the phrase against self-slaughter (“slaughter against one's self”). Compare Old English seolfcwalu (“suicide”), Old English āgenslaga (“suicide”).
self-slaughter (plural self-slaughters)
- The slaughter or slaying of one's self, suicide.
- Against self-slaughter, There is a prohibition so divine, That cravens my weak hand. --Shak., Cymbeline