To be mixed; to mingle — an intransitive verb meaning two or more things become blended or join together (used for liquids, colors, people, etc.).
砂糖が水にしっかり混ざるまでかき混ぜてください。
Stir until the sugar is fully dissolved/mixed into the water.
新しい社員はすぐに職場の雰囲気に混ざった。
The new employee quickly fit in with the workplace atmosphere.
赤と白の色が混ざってピンクになる。
Red and white mix to become pink.
彼の話には冗談が混ざっていた。
There were jokes mixed into his talk.