1) American: bonkers (I think I am going \<b\>bonkers\</b\>), nuts (You are completely \<b\>nuts\</b\> if you think I will go with you)
2) Jocular: fruity-loops (UK)
3) Abbreviation: czy
Универсальный русско-английский словарь. Академик.ру. 2011.