1, 9. Mix, blend, combine, mingle concern the bringing of two or more things into more or less intimate association. Mix is the general word for such association: to mix fruit juices. Blend implies such a harmonious joining of two or more types of colors, feelings, etc., that the new product formed displays some of the qualities of each: to blend fragrances or whiskeys. Combine implies such a close or intimate union that distinction between the parts is lost: to combine forces. Mingle usually suggests retained identity of the parts: to mingle voices.

Did you mean mix up?