A more thorough explanation:

A manifest thief, also known as fur manifestus, is a term used in Roman law to describe a thief who is caught in the act of stealing. The term "manifest" refers to the fact that the theft is clearly evident and can be proven without a doubt.

If a fur manifestus was caught stealing at night or used a lethal weapon against the person who discovered the crime, they could be put to death on the spot. In other cases, the thief was required to pay the owner four times the value of the stolen property.

For example, if someone was caught stealing a valuable item from a store during business hours and was caught in the act, they would be considered a manifest thief. However, if someone stole something from a store and was not caught until later, they would not be considered a manifest thief.

The term "manifest thief" is no longer used in modern legal systems, but it provides insight into the severity of theft in ancient Rome and the harsh punishments that were imposed on those who were caught in the act.