malice aforethought

noun Law.

1. a predetermination to commit an unlawful act without just cause or provocation (applied chiefly to cases of first-degree murder).

noun criminal law

1. the predetermination to do an unlawful act, esp to kill or seriously injure
2. the intent with which an unlawful killing is effected, which must be proved for the crime to constitute murderSee also murder, manslaughter