Green’s Dictionary of Slang

(Aus.) a fool, a simpleton.

1950

1950196019701980

1981

1950, 1955		‘No. 35’ Argot in G. Simes DAUS (1993).
1953		Baker Aus. Speaks.
1974		J. McNeil How Does Your Garden Grow Act III: I reckon. Top idiots. Imbos.
1981		P. Radley Jack Rivers & Me 50: ‘What is an imbo, Connie? Please?’ ‘If you don’t know what imbeciles are far be it from me to tell you,’ Connie said.