Bill Zebub
“It’s probably Matt Mercer’s fault.”
That's why I'm suggesting "munchkin".
I always thought "munchkin" referred to a gonzo playstyle that requires the participation of the DM. Its hallmarks are things like stats "fudged" to the breaking point, powerful magic items falling like rain, everybody somehow getting an 01 on their psionics roll, monsters making terrible decisions that allow them to be easily defeated, etc. etc. etc.
It goes way way beyond "optimization," which I think of as something that occurs within both RAW and RAI, and which often annoys people who think it's fun to play non-optimized characters.