A more thorough explanation:

Malice aforethought is a legal term that refers to the mental state required to prove murder in the first degree. It means that the person who committed the murder had the intention to kill or cause serious harm to another person.

There are two types of malice: express and implied. Express malice is when a person intends to cause harm or death to another person. Implied malice is when a person commits a felony or displays a depraved indifference to human life, resulting in someone's death.

For example, if someone plans and premeditates to kill their spouse, that would be considered murder with express malice. If someone robs a bank and accidentally kills a security guard, that would be considered murder with implied malice.

Today, malice aforethought is still used in federal law and some states to define murder in the first degree. However, many states have abandoned this language and instead focus on intent and premeditation.

Overall, malice aforethought is an important legal concept that helps determine the severity of a murder charge.