muddle up (third-person singular simple present muddles up, present participle muddling up, simple past and past participle muddled up)
- (transitive) to confuse (one or more objects with another object or other objects)
- Whenever I meet the twins, I always muddle up their names. I call John Jim, and Jim John.
- (transitive) To mix together
- muddle up the letters in the word, and try to make new ones.