Unfattened, a term used to describe something that has not been fattened or made plump, can be substituted with a variety of synonyms. Some words with similar meanings include lean, thin, skinny, slender, emaciated, undernourished, gaunt, and scrawny. These words are often used to describe animals, particularly livestock that has not been given feed or supplements that would lead to weight gain. The aforementioned synonyms can also be used when discussing weight loss or dietary habits in human beings. Overall, the use of synonyms provides a diverse and flexible vocabulary that can accurately convey a message or idea.