Attractiveness is a subjective term that refers to the quality of being pleasing, desirable or alluring. However, if we talk about the opposite of attractiveness or unattractiveness, there are several antonyms that describe the lack of appeal, beauty or charm. Some of the antonyms for un-attractiveness include ugliness, repulsiveness, unpleasantness, unappealingness, unsightliness, and unloveliness. These words describe features or qualities that are not pleasing to the eye, such as deformities, disfigurements, or flaws in physical appearance or behavior. While everyone has their unique perception of beauty, these antonyms of un-attractiveness are universal in describing a lack of appeal in various aspects.