A more thorough explanation:

Malum prohibitum

Malum prohibitum refers to an action that is considered immoral or wrong because it is prohibited by law, but it may not necessarily be inherently wrong or immoral.

• Driving above the speed limit is considered malum prohibitum because it is against the law, but it may not necessarily be immoral or wrong in certain situations.
• Using marijuana in some states is malum prohibitum because it is illegal, but it may not be considered inherently wrong or immoral by some individuals.

The examples illustrate that malum prohibitum actions are not necessarily wrong or immoral in themselves, but are considered so because they are prohibited by law. In some cases, the actions may be acceptable or even necessary in certain situations, but are still considered illegal.