Drifter - Someone who can't stay in one place. Sometimes homeless and jobless, but capable of securing either with relative ease, the drifter is moved more from itchy feet and an innate desire to see what's on the other side of the hedge than he/she is a victim tossed about by their personal incompetencies. The drifter prefers to keep moving, but can still fit into society seamlessly when so desired. If properly balanced and absent of malice, the drifters' ephemeral company can be an asset to any social circle.
Hobo - Just like the drifter, the hobo has itchy feet. But the hobo has departed from the laws of polite society entirely. In manner, speech, clothes, and hygiene, the hobo is unafraid to announce his or her true state of standing. Though driven to life as a transient by (at the very least) an aptitude for wrong choices, the hobo has the wherewithal to make a game of their poverty, choosing to view it through the eyes of an enlightened philosopher rather than an abject failure. Hobos are not to be coddled in the public eye, but can be an invaluable source of wisdom when chance brings one into their company.
Bum - The bottom of the panhandling totem pole. The bum aspires to get back to the charmed life of the drifter, but is most often too fundamentally broken to move in any direction but downwards. Whether it be mental illness, a penchant for self-destruction, or a savant-like application of poor decision making, the bum just can't win. Thus, he or she is in a perpetual state of begging for help from a general public that they despise. Bums are wont to shit on sidewalks and yell racial epithets in the small hours of the morning. And though they are worthy of compassion, they are to be engaged with the utmost caution as their history of human interaction is a black hole of deficits.