1. Someone who is not able to converse easily or pleasantly with other people in a social setting or event. I was worried about bringing my girlfriend out to the party—he's a bad mixer when she's around a lot people she doesn't know.

2. A non-alcoholic beverage that pairs well with a particular type of alcohol. Let that be a lesson going forward—milk is a terrible mixer with gin.

1. Someone who is able to converse easily and pleasantly with other people in a social setting or event. I was worried about bringing my new girlfriend out to a party with so many people he had never met before, but luckily she's a really good mixer.

2. A non-alcoholic beverage that pairs well with a particular type of alcohol. I turned my nose up when he started pouring tomato juice into the glass, but apparently it's a really good mixer with vodka.