A Naming Seer is a witch or wizard, skilled in Divination, who uses this skill to predict the future of a newborn baby. The parents, who pay a handsome fee for this service, use this information to choose a name for the child (Pm:NamingSeers).
While most witches and wizards simply choose names that they like for their children, some still follow the ancient wizarding tradition of consulting a Naming Seer to use Divination to predict what their child will be like and suggest an appropriate name for them. Naming Seers command a large fee for this service (Pm:NamingSeers).
Perhaps Rowling included this information as a reason for all the unusually spot-on names for characters in the Wizarding World. Remus Lupin, for example, was certainly given a particularly appropriate name as a baby, which suggests that his parents had some idea he would become, well, fond of wolves growing up. --SVA