Green’s Dictionary of Slang

Rhodes scholar n.1

[the scholarships established by Cecil Rhodes (1853–1902), sending students born and educated in the then British colonies (incl. the US) to Oxford University]
(Aus. Und.)

1. a derog. description of someone the speaker feels is trying to set themselves above the mass.

[Aus]‘No. 35’ Argot in G. Simes DAUS (1993).

2. a non-derisive phr. of thanks for a favour done, you’re a Rhodes scholar, mate.

[Aus]‘No. 35’ Argot in G. Simes DAUS (1993).