Green’s Dictionary of Slang

1. (Aus.) drunk [full adj. (1)].

1914

Bulletin (Sydney) 10 Sept. 24/4: Manifestly some publican had disregarded laws made and provided to cut the aboriginal off from his drink. Jacky was more than moderately ‘foo.’.

2. (US campus) stupid [? SE foolish or foo-foo adj. (1)].

2014

C. Eble (ed.) UNC-CH Campus Sl. Spring 2014 6: FOO — fool result of a failed attempt at something: ‘She tried to cut her own hair, but she looked foo’.