Green’s Dictionary of Slang

(orig. Anglo-Ind.) to wash clothes; thus dhobi dust, washing powder.

1907		South Eastern Times (Millicent, SA) 11 Jan. 6/6: The most profitable of all Jacks commercial undertakings is the ‘dobieing line,’ and in every large ship there are some half a dozen ‘dobie firms,’ consisting of from two to five members. ‘Dobie’ means nothing more or less, than washing.
1925		(con. WWI) Fraser & Gibbons Soldier and Sailor Words 79: Dobying: (Hind.—dhobi—a washerman). Washing clothes.
1945		D. Bolster Roll On My Twelve 80: Two such coves as Dicky Nolan and Crash Wade would stop very little short of murder to obtain [...] a ‘dhobi-bucket’. No ship ever had enough buckets [...] it would mean not only that they could use it for ‘dhobying’, that is washing their smalls, but they could hire it out.
1958		C. Lee diary 9 Feb. in Eight Bells & Top Masts (2001) 51: I’ve dhobi’d all my gear, but Ainslie says he can still smell me.
1971		(con. WWII) B. Aldiss Soldier Erect 64: A freshly dhobied suit of jungle greens.
1980		T. McClenaghan Submariners II i: Anyone got any dhobi dust? [...] He leaves with his laundry and Spider’s Daz.
1984		(con. WW2) T. Jones Heart of Oak [ebook] Dhoby, dhoby, never go ashore, / Finish up at the sick-bay door.
1997		(con. 1950s) D. Farson Never a Normal Man 177: They’d scrub their cabins for ’em and dhobi their things.
2023		R. Milward Man-Eating Typewriter 123: [T]his de-luxe floating colony he wanted to ethnically dhobi.