Bad dope can refer to drugs but also someone who’s Bad and you probably don’t want to associate with. Are known for for doing grimmy things. Usually have bad intentions or just no good.
Example:
Boy 1: "I’m gonna try to talk to Nay"
Boy 2: "Nah man don’t she bad dope I heard she be playing people"
quasi-dope refers to a situation or individual that appears not to be 'dope', but is infact quite dope. It means they are implicitly dope, and unaware of perhaps how dope they come across as being.
So in hindsight, you may look back at a situation and realize that actually, that was dope.
Johnny McGuire entered into the piss, with a newshirt on
Jack looked over at the Scou and remarked 'that's quasi-dope, don't you think'