mustelid Get Printable Handwriting Hear It! Say It! Write It! Learn It! Spelling Test Definition noun. a member of the weasel family of mammals. Example Sentence We saw a mustelid in the woods. More Example Sentences Mustelids include animals like ferrets and otters. Synonyms weasel; ferret; otter Antonyms giant; huge Hear It! Say It! Write It! mustelid Switch to cursive Start Share with your friends: