Vivi Reis. Actually, idioms(expressões idiomáticas) and slangs(gírias) are direfent terms. But some idioms can be considered slangs too. Okay, I'll explain you what's the direfence between both.
- IDIOMS -> Idioms are expressions that their meaning cannot be understood or translated literally(ao pé da letra)... For expample:
To beat around the bush -> Enrrolar (de ficar "enrrolando" pra fazer / fazendo algo (to goof off));
It's my cup of tea -> É do meu tipo, do que sou bom, é comigo mesmo
- SLANGS -> Slangs are very informal words or expressions that are used in very informal chats like we all know in Portuguese, such as: "e aí veio?", "beleza irmão?", "sussa?". In English it's not different. Examples:
- dude -> cara, veio;
- chicken -> relacionado a garotas (ex: I kissed that chicken yesterday night);
- what's up? -> E aí?
I hope I helped you... Good studies for you, dude... Tks.