In my english book in school

The English word "Deal" means "Sälja Narkotika" in swedish. wich is selling drugs.
so, Dont you accept if anyone wants to make a deal with you!

 

In French we have this phrase "faire du deal" where this word 'deal' comes from English (of course). This expression means "sell drugs", or generally make an illegal business.

 

That's why, here in America, they're called drug dealers.

 

...

 

but deal isn't generally selling drugs, but more like an agreement

 

A deal is an agreement.

To deal is to sell drugs. Or I suppose start a poker game.

If I were to just randomly call someone a dealer, unless I was in Las Vegas, the person I was talking to would immediately assume I meant a drug dealer.

 

but if you said you made a deal with someone they don't assume you sold/bought drugs.

 

Well are you talking about the verb or the noun?

 

Noun. So no, that doesn't refer to drugs, supah.