Bludger is a slur used to describe Australian aboriginals in a derogatory way. A bludger, or more accurately "dole-bludger", in Australian slang is someone who doesnt work and relies on the government for money (doles). It is the sterotype that all the Mediterraneans and Aborigianals of Australia are bludgers.
The word Bludger is a racial slur that has been used historically to degrade and dehumanize australian aboriginals. The word is still used by some people for this purpose, and it is seen as offensive and hurtful to australian aboriginals. If you are unsure about whether or not it is appropriate to use the word Bludger, it is best to err on the side of caution and avoid using it in any situation.