Mix up is an idiom used to refer to confusing two or more things. It can take numerous forms and meanings depending on the context in which it is used. Some synonyms for mix up include jumble, scramble, confuse, muddle, disarray, disarrange, blend, shuffle, intermix, and agitate. Each has its unique usage and connotation in a sentence. For instance, jumble refers to mixing several things in a disorderly way, while scramble means to mix or blend rapidly and forcefully. Similarly, the word muddle refers to a confused state of a situation, while agitate means to mix something by shaking or stirring it. By using different synonyms, you can vary your language and avoid repetitive expressions when speaking or writing.