Green’s Dictionary of Slang

1. (orig. US) an assistant to a driver of horses, mules or bullocks.

1870		Dly Territorial Enterprise (Virginia City, NE) 21 Apr. 3/1: A ‘swamper’ is a man who goes with the driver of a 10, 12, or 14-mule team as his assistant – the driver being chief engineer and the swamper first-assistant [OED].
1926		K.S. Prichard Working Bullocks 6: His swamper yelled and danced, brandishing a long, hard strip of wet bark over the polers.
1954		T. Ronan Vision Splendid 94: I’m the only swamper in this camp.

2. (Aus.) one who travels on foot but has his pack carried on a wagon.

1894		Bulletin (Sydney) 28 Apr. 9/3: Teamsters are now arriving with nothing but swags aboard, the ‘swamper’s’ baggage being more remunerative than ordinary loading.
1917		T.J. Briggs Life and Experiences 126: I had with me two drivers and nine swampers. These latter were men who were making for the goldfields with their swags, and they paid me £4 each to carry their swags, and walked themselves [AND].
1930		H. Redcuffe Yellow Cygnet 123: Swampers [...] were those who, having no carriage but their legs, at a price arranged with the teamster, dumped their swags containing food and blankets on his dray, while they followed on foot throughout the journey [AND].
1941		Baker Popular Dict. Aus. Sl.
1954		T. Ronan Vision Splendid 21: If Sidi picked up any swampers it was a safe bet that some of the luxury goods would be short on arrival .
1972		N. King Nickel Country 48: Many men loaded on their swags and walked beside the wagons. They became known as ‘swampers’ and they soon learned to walk ahead of the wagons to avoid the choking dust .
1983		P. Adam-Smith When We Rode Rails 70: Some who walked while paying to send their swags ahead on a wagon were called ‘swampers’ [AND].

3. (US tramp) a bar room cleaner.

1907		Oregonian 13 Oct. n.p.: He was a swamper in a saloon [DA].
1911		Oregonian 30 Aug. n.p.: John M. Johnson [...] was employed as a ‘swamper’ in a San Francisco saloon [DA].
1929		Collier’s 5 Jan. 33/1: As a result it became pay dirt, and in later years the swamper actually had to pay for his job [DA].
1930		‘Dean Stiff’ Milk and Honey Route 215: Swamper – Fellow who cleans out the bar-room.

4. a truck- or van-driver’s assistant.

1929		V.W. Saul ‘Vocab. of Bums’ in AS IV:5 345: Swamper—A helper on an auto truck.
1949		A.I. Bezzerides Thieves’ Market 114: ‘That’s my swamper,’ the driver said. [Ibid.] 232: He saw Nick run to his truck. The swamper waddled after him. ‘You’re going to let me swamp for you huh?’.
1967		(con. 1920s) J. Thompson South of Heaven (1994) 69: The truck swampers stood on the running boards.
1977		E. Bunker Animal Factory 196: We’ve got to check out the swampers . . . make sure they aren’t stool pigeons.
1981		J. Ellroy Brown’s Requiem 151: I learned that there was a fleet of tuna boats coming in today and that a large number of swampers would be needed to unload them.
2001		(con. 1964–8) J. Ellroy Cold Six Thousand 259: Wayne tossed crates. A swamper stacked them.

5. (Aus.) one who obtains a lift.

1964		H.M. Barker Camels and Outback 14: On this journey one of my three passengers (or ‘swampers’) would ride ahead on the horse to pick a camp [AND].
1966		T. Ronan Once there was Bagman 15: My [...] fellow swamper tossed his swag off [the mailman’s truck] here; he was home.

6. (US Und./prison) a cleaner, esp. a prisoner working as a cleaner.

1949		Monteleone Criminal Sl. (rev. edn) 230: swamper A janitor who scrubs floors.
1952		W.D. Overholser Fabulous Gunman 41: The swamper sloshed a bucket of dirty water into the street.
1955		‘Blackie’ Audett Rap Sheet 209: One day a new fish come in as a swamper. The fish was swinging his mop, trying to make a big show.
1966		F. Elli Riot (1967) 29: Mess-hall swampers in sweat-plastered T-shirts.