It’s funny because I’ve got an interest in booze but I’m also really into coffee and they’re slightly different.

With coffee, it doesn’t have any natural sweetness really, at least not like with wine. Generally describing a coffee as sweet means a nice balance of bitterness and acidity such that neither is overpowering. Sweet, more in the way of being pleasant, rather than sugary. And usually bitter and sour are the polar opposites. Whereas with booze, I think you’re right in that most people see sweet and bitter as opposites.

With that being said, dry is always the opposite of sweet with regards to professional tasting, at least for coffee and wine. I’m not sure about beer and spirits.