As you said, not to be confused with the word classic.
I think there's very few rap albums that are
masterpieces. And that is a very strong word that I think needs to be justified on many fronts. And one rap album that without a doubt in my mind, is a masterpiece and which I could argue for being so is...

Again. We're talking
masterpiece. And, I've seen people mention what I consider classics but... I mean, I saw
Chronic 2001 mentioned for example. Now, a classic? ABSOLUTELY. But A fucking
masterpiece? an otherwise typical gangsta rap album aside from Dre's production...
Not in my opinion.
I think that word should be reserved for works of art that defy cliche and go against the grain to such extreme degrees that they blow everything before it to pieces and ooze originality. And, in the case of
The Marshall Mathers LP it not only did that but... its paradoxical format and what Em did with it was just absolute reactionary genius.
It was more than an album. It was a statement, and a divisive bombshell.
I also think that it's Em's only masterpiece by the way.