Mix  —v. 1 combine or put together (two or more substances or things) so that the constituents of each are diffused among those of the other(s). 2 prepare (a compound, cocktail, etc.) By combining the ingredients. 3 combine (activities etc.) (mix business and pleasure). 4 a join, be mixed, or combine, esp. Readily (oil and water will not mix). B be compatible. C be sociable (must learn to mix). 5 a (foll. By with) (of a person) be harmonious or sociable with; have regular dealings with. B (foll. By in) participate in. 6 drink different kinds of (alcoholic liquor) in close succession. 7 combine (two or more sound signals) into one. —n. 1 a mixing; mixture. B proportion of materials in a mixture. 2 ingredients prepared commercially for making a cake, concrete, etc.  be mixed up in (or with) be involved in or with (esp. Something undesirable). Mix it colloq. Start fighting. Mix up 1 mix thoroughly. 2 confuse. [back-formation from *mixed]