Definition - What does Malice Aforethought mean?
Malice aforethought is the term used to describe an offender's calculated intent to seriously hurt or kill someone prior to the commission of a legally unjustified or inexcusable act. As such, it is one of the elements that must be proven in order to secure a conviction for first-degree murder.
Justipedia explains Malice Aforethought
The term "malice aforethought" is used only to describe an offender's intent prior to the commission of a lethal crime. It is not used to describe an offender's emotions or feelings about the victim.
Because it speaks to intent, malice aforethought is not applicable in cases where someone kills another person in self-defense, or if someone was clinically insane prior to and during the commission of the offense. However, it is applicable in cases where the offender acts with supreme carelessness or disregard for another life.