A more thorough explanation:

Definition: Malus animus is a Latin term used in Scots law to refer to bad intention. It is the intention to commit a crime, which when coupled with a prohibited act, results in the commission of a crime. This is also known as mens rea.

For example, if someone intentionally sets fire to a building, they have malus animus because they had the bad intention to commit the crime of arson. Similarly, if someone steals something with the intention of keeping it for themselves, they have malus animus because they had the bad intention to commit the crime of theft.

Another example would be if someone plans and carries out a murder. They have malus animus because they had the bad intention to commit the crime of homicide.

These examples illustrate how malus animus is the intention to commit a crime, which is an essential element in determining criminal liability.