Though they can be annoying, people who bludge—bludgers—are relatively harmless. On the other hand, a bully armed with a bludgeon—a "bludgeoner"—can cause serious harm. In the 19th century, bludgeoner was shortened to bludger and used as a slang word for "pimp." That bludger was certainly a kind of bully, one apparently willing to wield a bludgeon now and then to insure his livelihood. In the early 20th century, bludge became the verb for what a bludger does. By then, a somewhat softened bludger had appeared in Australia and New Zealand: the pimping and the bullying were eliminated, and the parasitical tendencies reduced to mere cadging or sponging.
Word History
Etymology
back-formation from British argot bludger pimp, probably contraction of bludgeoner one wielding a bludgeon, from bludgeon