Green’s Dictionary of Slang

1. (also clapdish) idle chatter, meaningless, often positively incorrect or misinformed talk; also as adj.; thus also claptrappy, nonsensical.

1611		J. Cook Greenes Tu Quoque Scene xvii: Widow, hold your Clapdish, fasten your Tongue Unto your Roofe, and do not dare to call.
1821		‘An Amateur’ Real Life in London I 400: Worn-out sentiments and clap-traps will be taken in exchange.
1837		‘The Butterfly Bishop’ Bentley’s Misc. July 23: As a self-satisfied orator does when about to enforce some some appalling clap-trap sentiment.
1837		Thackeray Yellowplush Papers in Works III (1898) Intro: This sounds like claptrap, but I fear it will be true.
1849		G.G. Foster N.Y. in Slices 14: He does not take you by storm – he uses no clap-trap – he despises all such vulgar auxiliaries.
1851		H. Mayhew Comic Almanack 37: She will [...] wait for the next bankruptcy rather than visit some house where honest prices prevent clap-trap trickery.
1860		Hotten Dict. of Modern Sl. etc. (2nd edn).
1864		E. Wardley Confessions of Wavering Worthy 97: That theatrical, clap-trap, but still magnificent empire.
1865		Yorks. Gaz. 22 July 4/6: It was a piece of clap-trap to catch the farmer.
[1869		Western Gaz. 14 May 3/2: Yankee Clap-Doodle].
1876		Raleigh Sentinel (NC) 26 Aug. 1/2: Fellow-citizens, don’t be deceived [...] by any such clap-trap humbuggery.
1877		Dodge City Times 13 Oct. in Miller & Snell Why the West was Wild 327: Pledges are usually considered before election to be mere clap-trap.
1880		Bulletin (Sydney) 7 Feb. 1/1: Perhaps it is because the latter has not hitherto been brought before us, and that a foolish pride, fostered by the clap-trap of gabbling politicians, has as yet forbidden us entertaining the idea of poverty in this virgin country.
1892		‘John Miller’ Workingman’s Paradise 200: That’s only clap-trap.
1895		Crowe Aus. Sl. Dict. 17: Claptrap, high-sounding nonsense.
1901		W.A. Sun. Times (Perth) 9 June 1/1: Sundry Perth lawyers stand badly in need of a course of lessons in police court deportment [...] inane clap-trap, while other pleaders have the floor, is the daily diversion of the briefless.
1901		Bulletin (Sydney) 14 Dec. 36/1: Sounds a bit claptrappy, and, in fact, Kiplingesque. But, then, Bullen was addressing a total-abstinence society, and the cold-tea anecdote is mostly lie!
1901		Marvel XV:373 Jan. 4: It ’ud be a cold day afore I’d shift for a claptrap badger like Dunk Doolan.
1903		A.H. Lewis Boss 295: There’s no more empty claptrap than this claptrap of family.
1913		A. Lunn Harrovians 214: So pray don’t weary me with the clap-trap of stale sarcasm.
1922		A. Christie Secret Adversary (1955) 143: They call it heart failure induced by an overdose, or some such claptrap.
1930		D. Mackail Young Livingstones 243: Girls who weren’t deceived by all this clap-trap.
1945		E. Rutherford 13 Dec. diary in Garfield Our Hidden Lives (2004) 147: I had to listen to a lot of the usual Tory claptrap.
1956		J. Curtis Look Long Upon a Monkey 134: What you haven’t explained is how, if you’re sincere about this tu’penny/ha’penny, disloyal claptrap, you put up such a damn good show in the scrap.
1960		(con. 1953) A. Wesker I’m Talking About Jerusalem II i: Don’t take any notice of that clap-trap.
1977		E. Torres Q&A 75: We are [...] victims of a thousand years of popery and Thomistic claptrap.
1983		M. Read Scouting for Boys in Best Radio Plays (1984) 164: You know what I can’t stand about your half-baked Marxist clap-trap? There’s no joy. No one smiles.
1994		B. Fallowell One Hot Summer in St Petersburg 191: Why am I listening to such odious claptrap?
2000		Guardian Rev. 22 Jan. 7: Sometimes you need people to say it is all meretricious claptrap.
2010		K. Richards Life 540: ‘Give me painkillers, for Christ’s sake!’ ‘We can’t do it in the air.’ Four hours of this claptrap.
2023		R. Milward Man-Eating Typewriter 47: [I]njecting me with this cateva atomic fear and reckless carpe-diem claptrap.

2. any device used to milk an audience for applause.

1809		B.H. Malkin (trans.) Adventures of Gil Blas (1822) II 8: I scraped together in my memory all the clap-traps in our stock plays, which were most successful with the audience.
1840		London Mag. Feb. 82/1: There are some vile clap-traps interspersed throughout the play [...] which were very properly hissed, and, as a necessary consequence, subjected to the pruning-knife.
1898		(con. 1875) F.T. Bullen Cruise of the ‘Cachalot’ 126: Shall I be laughed at when I confess that our musical efforts were confined to Sankey’s hymns? [...] Cheap and clap-trap as the music may be, it tasted ‘real good’.
1926		Wood & Goddard Dict. Amer. Sl. 11: claptrap. Cheap unworthy trick to get applause.

3. fraudulent, persuasive patter.

1884

Peterhead Sentinel 6 Feb. 1/2: Genuine Sale all the year round [...] no clap-trap whatever; all fair and above board; but we cannot stand priggin’ — na hae seen.

4. (US black) the mouth.

1914		Sport (Adelaide) 25 Sept. 5/4: It is a pity L S could not shut her clap trap instead of trying to run other girls’ characters down.
2005		Mad mag. Oct. 34: Rest yer claptrap.

5. see rattletrap n. (2b)