What does it mean "goró"? It is word from Portuguese.
hypothesis: is it a slang for alcohol
And what is its grammatical gender?
In Brazilian Portuguese, "goró" is a slang word used to refer to alcoholic beverages (usually vodka, whisky, beer, etc.), but can also mean specifically the "cachaça". It's gender is masculine, so if you want to say that you will have a drink, it could be said as:
Vou tomar um goró.
Or in the plural:
Vou tomar uns gorós.
It's not so common, but sometimes you still hear someone say this slang, although it's not at every region in Brazil that people will know what "goró" means.
Adding to the other answers, goró is a male gender word, but I wouldn't say that it is exactly a slang for alcoholic beverages.
It's more an informal term used when someone intends to drink a lot and not specifically one kind of beverage. For instance, if you're going do drink a bottle of wine, you wouldn't "let's have a goró", it's more used when you are, let's say, going to a party and you intend to drink as much as you can, then you can say "let's have a goró!"
BTW, it's used in this sense in some musics, like this one.