Green’s Dictionary of Slang

1. Dublin.

1922

Joyce Ulysses 424: Best value in Dub.

2. (also Dubbo) a Dubliner.

1849		A. Harris Emigrant Family I 273: ‘Hunt ’em all up, Dubbo,’ said the Black. [...] As he was directed the Dubliner crowded the mob in which the huge sulky-looking animal stood.
1901		Mercury (Hobart, Tas.) 22 Apr. 2/8: I said to one of the Dubs, ‘What are you having for breakfast, ham and eggs?’.
1982		E. Mac Thomáis Janey Mack, Me Shirt is Black 11: Two real Dubs, with wit at their fingertips and bargains at their stall.
1996		P. Howard The Joy (2015) [ebook] ‘More fucking Dubs!’ this real aggressive Cork voice shouted. ‘This place is already bursting’.
2015		L. McInerney Glorious Heresies 213: One of the Dubs had volunteered to cut his throat.
2021		Breen & Conlon Hitmen 9: They got in a row with ‘a couple of Dubs’.