Don't mix it. It's dangerous!
It's incredibly tasty when you mix tonkatsu sauce with mayonnaise.
Hey, you should watch out, I saw that guy mix something into your drink.
This word consists of kanji with hiragana attached. Because the hiragana ends with an う sound, you know this word is a verb. The kanji itself means mix so the verb vocab version is to mix. This is when you're doing the mixing. You can remember this because "there (ぜる) is much mixing to be done so it's best if you just do it because nobody else will."
The connotation for this word is you can't distinguish the things you're mixing, like combining paints, which become one mixed color that isn't two separate colors anymore.
Since this word consists of a kanji with hiragana attached, you can bet that it will use the kun'yomi reading. You didn't learn that reading with this kanji, so here's a mnemonic to help you: You're doing mixing like your ma (ま) taught you, which is why when you do the mixing things get done around here a lot faster.
You can also use the level 5 vocab 交ぜる to help you remember as it has the same meaning and reading!