Unguis is a term used to describe the nail or claw of an animal or bird. There are a number of synonyms you can use for this word, depending on the context of your writing. For example, you could use the word talon to refer to the sharp, curved claws of birds like eagles and owls. Other synonyms for unguis include hoof, for the hard, unfeeling nails of horses or cattle, and claw, for the sharp, hook-like nails of animals like cats and bears. Whatever word you choose, make sure it accurately conveys the nature and function of the animal's nails.