A combination of two words in two different languages. Sian, in hokkien, means bored. Bodoh, in Malay, means stupid. While the combination of these two words makes no sense whatsoever, it is widely believed that this term was coined to build rapport with the Malays.
*In a classroom scene*

K.O: eh sian bodoh!
Jack: why are you speaking like a damn malay?
K.O: so that I can establish some sort of a bond with the malays
Jack: AAahahahahahah
Class: AAHAhhahahahaa
Malays: what's so funny?
by The Black Jack March 6, 2008