Munanga, ‘white person’ is widespread among the languages of the Arnhem Land region
as Jay Arthur (1996:161) notes in her compilation of written Aboriginal English, supported by citations from the northern NT 1977-1995.1 This extends to the present, as Wamut that munanga linguist can testify.
I was intrigued to learn recently that scholars don’t have much of an idea of the origin of the word. The AND (Australian National Dictionary 1988), now available online, has the earliest written citation
1912 Bulletin (Sydney) 15 Feb. 13/2 There is the much less widely known aboriginal term ‘myrnonga’. The myrnonga is a person of more promiscuous habits [than the combo] who – prowls with furtiveness when the moon is young.
but this is under the obscure headword murlonga ‘A white man who sexually exploits Aboriginal women’, with etymology
[Poss. a. Yolŋu sub-group munaŋa a white person.]2