A slander name for Indonesia, just like Indonesial and Indon. It's used by Malaysians who are called Malingsia, Malonsia, Malaysial, etc. which are also a bunch of slander names.
Indon = Indonesian. Like
nigga, if you're an Indonesian and use it, no problem. But if you're not and use it, this will offend them.
Sial =
Idiot. Commonly insult word.
This word sometimes comes with
pig (babi) and
dog (anjing) in the sentence, which are considered haram by both Malaysians and Indonesian.