A more thorough explanation:

Definition: Condicio si sine liberis decesserit is a Latin term used in Roman law. It refers to an express or implied clause in a will that states that if the heir or legatee dies without having any children, the property will go to another person, such as the testator's own descendants.

Example: For instance, if a person writes a will and leaves their property to their nephew, but adds a condicio si sine liberis decesserit clause, it means that if the nephew dies without having any children, the property will go to the testator's own children or grandchildren.

This clause is used to ensure that the property remains within the family and does not pass on to someone outside the family if the original heir or legatee dies without having any children. It is a common practice in estate planning and helps to ensure that the testator's wishes are carried out even after their death.