WordNet sense 1 (a disreputable vagrant):

bum, hobo

WordNet sense 2 (a foot traveler; someone who goes on an extended walk (for pleasure)):

hiker, tramper

WordNet sense 3 (a commercial steamer for hire; one having no regular schedule):

tramp steamer

WordNet sense 4 (walk heavily and firmly, as when weary, or through mud):

pad, plod, slog, trudge, footslog

WordNet sense 5 (move about aimlessly or without any destination, often in search of food or employment):

cast, drift, ramble, range, roam, roll, rove, stray, swan, vagabond, wander

WordNet sense 6 (a long walk usually for exercise or pleasure):

hike, hiking