Most pileous refers to something that is the most hairy or woolly in nature. Synonyms for the word most pileous include shaggy, furry, downy, fluffy, and tufted. Shaggy refers to something that has long, rough hair that is tangled and unkempt. Furry is used to describe something covered in soft fur or hair. Downy refers to something that is soft and fluffy, like the down feathers of a bird. Fluffy is used to describe something that is light and full of soft, airy fibers. Tufted refers to something that has clusters of hair, fur, or plants that grow closely together. These words all describe something that is most pileous in its appearance and texture.