Curvaceousness is a term that refers to the voluptuousness or curviness of a person's body. It is used to describe someone with a shapely and well-proportioned body. Antonyms for curvaceousness would thus be terms that describe a lack of curves or shapeliness. Words like angular, bony, emaciated, gaunt, skinny, scrawny, and slender are all antonyms that describe individuals with less voluptuous bodies. Additionally, words like shapeless, featureless, and unshapely can also be used as antonyms for curvaceousness. These terms are often used in a less flattering context and depict a less desirable body type.