A fork of Rural Dictionary
One of the things people call the VTuber Mori Calliope. It's tsundereaper because she's basically the grim reaper, and she literally acting like a tsundere. So, it was chosen as tsundereaper.
Person A: *watching a Mori Calliope stream and she starts acting like a tsundere*
Person A: Haha, tsundereaper.