Green’s Dictionary of Slang

skink n.

[? link to SE skink, a lizard]

(UK black) a term of abuse for a white person.

[Aus]Age (Melbourne) 11 June 13/2: A list of epithets gathered from parliament during the last year: piece of garbage [...] orangutan [...] poofter [...] yapping yahoo [...] four-eyed ape, skink [...] gutter dingo.
[US]D. Burke Street Talk 2.