A more thorough explanation:

The last-proximate-act test is a legal term used in criminal law to determine whether an individual has attempted to commit a crime. This test is based on whether the defendant has performed the final act necessary to commit the offense, such as pulling the trigger of a gun instead of just aiming it.

For example, if someone aims a gun at another person but does not pull the trigger, they have not committed attempted murder under the last-proximate-act test. However, if they do pull the trigger, even if the gun does not fire, they have committed attempted murder.

While this test was once commonly used, most courts have now rejected it as being too lenient. Instead, they use a more comprehensive approach to determine whether an individual has attempted to commit a crime.