The phrase "sine prole" refers to an individual or thing without offspring or children. There are several synonyms that can be used to describe the same concept. One term is "childless," which means not having any children. Another term is "barren," which refers to a person or thing that is unable to produce offspring. "Infertile" is another synonym that can be used to describe a lack of ability to produce children. Finally, "sterile" is a term that can be used to describe a person or thing that is unable to produce offspring due to physiological reasons. These synonyms can be used interchangeably, depending on the context in which the phrase is being used.