A more thorough explanation:

Definition: Nefas (nee-fas) is a Latin term that means something that is not right or forbidden by the gods. It is also used to describe something that is against the law or custom.

Examples:

• Performing human sacrifice was considered nefas in ancient Rome.
• Breaking the law by stealing or killing someone is considered nefas.
• Engaging in incestuous relationships was considered nefas in ancient Rome.

The examples illustrate how nefas was used in ancient Rome to describe actions that were considered immoral, illegal, or against the will of the gods. These actions were not only frowned upon but were also punishable by law. The term nefas was used to emphasize the seriousness of these actions and to discourage people from engaging in them.