Oncezek 

when someone is being extremely retarded

quit being such an oncezek

Oncezek by oncezek April 16, 2022

OnceZen 

Someone who is a big fan of the K-Pop groups Twice and Nct. It is a combination of their fandom names Once and Nctzen.

“Hey what do u call a Twice and Nct fan again?”
— “A oncezen of course!”

OnceZen by Kdyukika January 22, 2022