Wolf-Blooded ("uragarum" in the First Tongue) are otherwise normal humans that have a trace of Uratha blood within them.
Wolf-Blooded are usually characterized as one of the direct relatives of a werewolf. It is not as simple, however, as treading geneaologies back to find an Uratha ancestor. The blood of the Wolf is a fickle thing and transmission has more to do with spiritual components than genetics.