Green’s Dictionary of Slang

a gypsy, esp. a half-breed gypsy.

1853		‘E.R.’ in Carpenter Juvenile Delinquents 129: Gipseys, romaneys, didycoys, ‘our people’, as they call themselves.
1882		C.G. Leland Gypsies 115: That lie which is the mental action [...] of the Romany, and especially of the diddikai, or half-breed.
1906		A. McCormick Tinkler-Gypsies of Galloway 263: Some of these Petulengros [...] are merely didakeis (half-breed Gypsies).
1921		P. & T. Casey Gay-cat 180: ‘Tu shan o didikai jin as Gypsy Frank?’ asked the other; ‘You’re the part-Romany known as Gypsy Frank?’.
1931		E. Blair ‘Hop-Picking Diary’ 19 Sept.–8 Oct. in Complete Works X (1998) 231: Didecai, a . . . a gypsy.
1935		X. Petulengro Romany Life 5: English gipsies [...] to-day are mostly diddikais.
1958		D. Reeve Smoke in the Lanes 45: Sometimes I am taken for a diddikai — and treated accordingly. [Ibid.] (Gloss. of Romani terms) 301: diddikai – a half-Romani. Often incorrectly applied to all contemporary travellers.
1977		D. Powis Signs of Crime 180: Diddicoy Gypsy, or associate of gypsies; Diddiki See Diddicoy.
1981		(con. c.1910) A. Harding in Samuel East End Und. 123: He was a Romany, a Didicai.
1989		in G. Tremlett Little Legs 29: They’re what we call diddicoys or pikeys, not true travellers.
1998		J. Milne Alive and Kicking 23: [S]ome jobsworth will accuse you of being a camped-out diddicoi and serve you with a ten quid overnight parking bill.
1999		Indep. Rev. 30 Nov. 2: He had observed that there were ‘didicois’ on the train.
2010		K. Richards Life 202: Sir Mark Palmer, page boy to the Queen and inveterate didicoy.
2013		New Statesman 23-29 Aug. 44/3: Travellers? We know who they are. Tinkers, pikers, didicoi.
2024		J. Meades Empty Wigs (t/s) 175: [H]orse thieves, rustlers, sly peasants, spongers, gyppos, dids, moochers, tatterdemalion mendicants and poachers.
2024		J. Meades Empty Wigs (t/s) 620: Bert Lugsden and Dimps Tozer [...] were made unwelcome by the estate agent and steward Major Dick Crawley. He disapproved of didicoys.