A mix, blend, or variety.

“Next time, let's ask a group with a different mix up.”

A confusion or reversal.

“I refuse to send them any more money until they fix this mix up.”

To mix or blend thoroughly and completely.

“She mixed up peat moss, humus, and compost to make potting soil.”

To combine thoroughly.

“All the smells of the food had mixed up together.”

To prepare something from ingredients that are mixed.

“She mixed up a batch of her own potting soil.”