Green’s Dictionary of Slang

(US, orig. milit.) in a very parlous state, whether from physical injury, emotional instability, the effects of drink and/or drugs.

1955		S.V. Baum ‘From ‘Awol’ to ‘Veep’’ in AS XXX:2 103: Derivative terms reported in popularity among government workers included fubb (‘fouled up beyond belief’).
2001		S. Dutch ‘Printing’ on University of Wisconsin 🌐 These were just a few of a host of World War II acronyms, including: [...] fubb: f***** up beyond belief.