Smallishnesses is a rather difficult word to find synonyms for, as it is a very specific term that describes something being somewhat small in size or quantity. However, there are several words that could be used to convey a similar meaning, such as diminutiveness, minuteness, and insignificance. These words all refer to something that is small or insignificant, and can be used to describe anything from a tiny object or feature to a person or idea that is not considered particularly important or significant. While smallishnesses is a unique term, there are certainly plenty of other ways to describe things that are on the smaller side.