If you are freeborn, you came into the world already a free person, not a slave. Old laws and stories use it when they talk about rights: a freeborn citizen. It does not mean your parents paid nothing at the hospital. You will also see Freeborn as a family name, from Old English. In today's English the adjective feels a bit literary or historical, because legal slavery is no longer the frame for most students' lives — but in a history class the word is still exact.