The phrasal verb "mix up" is commonly used in informal contexts and is slightly more uncommon in formal communication. It typically describes a situation where things are mistakenly combined or confused with one another. For example, "I mixed up the twins' names again!" indicates confusion between similar or identical items, people, or pieces of information. It can also denote a process of preparation, such as combining ingredients to create something new, like "mixing up a batch of cookies." In more serious contexts, "a mix-up" can refer to an error, as in paperwork or plans getting confused. Thus, its usage can vary from lighthearted mistakes to significant errors, but it stays mostly within casual or semi-formal discussions rather than technical or highly formal writing.
B1
PreIntermediate
1. To confuse two or more things or people.
I always mix up the twins because they look so similar.
He mixed up the addresses and sent the package to the wrong place.
She mixed up the dates for the meeting and missed it entirely.
2. To create confusion or pandemonium by disordering arrangements or plans.
The abrupt change in leadership mixed up the project's timeline.
The sudden cancellation mixed up everyone's travel plans.
A mistake in the schedule mixed up the whole day's agenda.
