I would go for "nincompoop"
It would be cool if rappers called each other nincompoops as an insult.

2:27
Bring back phat
Seinfeld’d
Need more rappers to say c***
Seinfeld’d
Need them to make the Seinfeld theme using only their voices
Meaning?
Someone roasts you with a funny joke? You got Seinfeld’d.
You fall down some stairs, and a person says “that’s a shame”. You got Seinfeld’d.
Play a sweet bass line intro and do several mins of observational comedy about the minutiae of everyday life? That’s right, you got Seinfeld’d.