Neato is a slang term that means cool or impressive. Common antonyms for this word include unimpressive, uncool, boring, lame, and dull. Other antonyms can also be used depending on the context, such as unexceptional, mediocre, ordinary, simple, or basic. If you want to express the opposite meaning of neato, you can use negative descriptive adjectives like ugly, disgusting, terrible, or horrible. You could also use phrases like "not impressive," "not interesting," or "not exciting." It all depends on the tone and connotation you want to convey. Overall, antonyms for neato are used to describe something that is the opposite of cool or impressive.