Green’s Dictionary of Slang

1. a snob; a member of the upper classes.

1869		Man about Town 9 Oct. 36/3: I was pleased to see the abode of my friends the Lardidardies, who are living in great discomfort at the back, still hermetically sealed.
1882		‘I Never Drink Behind the Bar’ in L. Levy Flashes of Merriment (1971) 280: Oh, your [sic] a lally cooler, Pete, a reg’lar la-di-da.
1883		Bristol Magpie 15 Feb. 13/1: Scene A well-known city bar. Three ‘Lah-di-dahs’ doing their matutinal cigarettes and ‘bittaws,’ ogling and chaffing the barmaid [etc].
1895		Coburg Leader (Vic.) 19 Oct. 4/2: He is an awful toffy bloke / A lardy dah you know.
1899		Rollit & LeBrunn [perf. Marie Lloyd] Hulloa, Huilloa, Hulloa 🎵 But yesterday I saw her - a perfect ladidah / Careering down New Bond Street in her Victoria.
1910		P.W. Joyce Eng. As We Speak It In Ireland (1979) 282: Laudy-daw; a pretentious fellow that sets up to be a great swell.
1916		T. Burke Limehouse Nights 240: He [...] stood back, only mildly interested in the lah-de-dah.
1920		(?) H. Lawson ‘A Wet Camp’ in Roderick (1972) 894: I’ve seen one of them fancy fisherman la-di-dahs down there by the river shoot a bird like a curlew and break its leg.
1928		Hecht & MacArthur Front Page Act II: If you want me you’ll have to take me as I am instead of trying to turn me into some lah de dah with a cane!
1932		(con. WWI) L. Mann Flesh in Armour 146: ‘Haw, haw, Constantia, some la de da’.
1959		I. & P. Opie Lore and Lang. of Schoolchildren (1977) 75: Toff, swell, snob, nob, big-wig, lord, or la-di-dah.
1977		C. Hope Ducktails in Gray Theatre Two (1981) 46: Vreks. ’s what I call them ... students and clerks and fancy-pants, la-di-das and cops and toecap sandals, khaki shorts and short back and sides ... they’re always against the jollers.
1983		P. Reading 5x5x5x5x5 3v: Posh puff clever shite / La-de-fuckin-da.

2. (also lardidaism) snobbishness, affectation; upper-class and/or wealthy hedonism.

1880		Bulletin (Sydney) 7 Feb. 6/1: Tottles’ assumption of refined elegance, with a sort of lardidaism is ‘immence,’ but nothing can exceed his reproof of Bung for his vulgarisms and mispronunciation.
1883		Nat. Police Gaz. (NY) 24 Nov. 6/3: An elegantly dressed young man with much of the ‘la-de-dah,’ not to say ‘dude,’ about him.
1887		in G.D. Atkin House Scraps 166: The young ’un goes to music-halls, / And does the la-di-da; / We are a shiney family, We are! we are! we are!
1901		W.S. Walker In the Blood 170: ‘Let’s go an’ ’ave a stroll in ’Yde Park,’ said Ted to Toby. ‘Do the lar-di-da a bit.’.
1903		A.H. Lewis Boss 253: [He] relapsed into his customary attitude of moral, mental Lah-de-dah.
1909		J. Ware Passing Eng. of the Victorian Era 165/1: La-di-da (Street). Elegant leisure, and liberal expenditure.
1916		‘Anzac’ On the Anzac Trail 159: Officers (Navy) very fine fellows [...] No side or laddy-da .
1943		M. Harrison Reported Safe Arrival 32: A ole sojer like Smudge, ’oo wz brought up proper, wiv no fancy lad-dee-dah.
1960		‘Nino Culotta’ Cop This Lot 216: So a coupla blokes come back from Italy or wherever they bloody been an’ bung on the lah-de-dah.

3. (US) an attractive girl or woman.

1886

Nat. Police Gaz. (NY) 21 Aug. 7/4: A nicely dressed young lady of about eighteen summers [...] walked leisurely down Howard street the other morning [...] She was what a Charles street dude would call a ‘daisy’ or a ‘lah-de-dah’.