When seeking alternatives to describe someone or something as "not beautiful," there are a plethora of synonyms to choose from. Some possible terms might include "unattractive," "plain," or "ugly." Other options could include "unappealing," "unpleasant," or "unsightly." Depending on context, additional words to describe the quality of "not beauty" might include "repulsive," "forlorn," "distasteful," or even "offensive." Ultimately, the selection of any of these synonyms - or any combination of them - would depend on the writer or speaker's intended meaning and the audience they hope to convey it to.