There are several synonyms for the term "hell hound," which is a ferocious canine of supernatural origin. Some of the words that can be used to describe this type of creature include demon dog, fiendish hound, supernatural beast, infernal canine, and devilish mutt. Other terms that can be used to describe a similar creature might include black dog, spectral hound, shadow hound, and phantom wolf. These creatures are often associated with darkness, evil, and the supernatural, and are often depicted in literature and mythology as fierce and terrifying beasts that lurk in the shadows and prey on unsuspecting victims.