Green’s Dictionary of Slang

tub-thumper n.

also tub-drubber, -hunter, -pounder, -puncher
[tub n.1 (2) + SE thumper/drubber; ‘from the old Puritan fashion of “holding forth” from a tub, or beer barrel, as a mark of their contempt for decorated pulpits’ Hotten (1864)]

1. a vehement preacher or orator, either clerical or secular.

[UK]Dr. Dodypoll in Bullen III (1884) III i: You are a sweet smell-feast, Doctor; that I see. Ile (have) no such tub-hunters use my house.
[UK]T. Brown in Works (1720) III 198: Business and poetry agree as ill together as faith and reason; which two latter, as has been judiciously observ’d by the fam’d tub-drubber of Covent Garden, can never be brought to set their horses together.
[UK]‘Nickydemus Ninnyhammer’ Homer in a nut-shell Dedication: Daniel Burgess, and most of those Tub-thumpers, who were Eminent for Pulpit-Drolls, and Sunday-Comedians.
[[UK] in D’Urfey Pills to Purge Melancholy II 165: A Country Bumpkin that Trees did grub, / A Vicar that us’d the Pulpit to drub].
[UK]Grose Classical Dict. of the Vulgar Tongue n.p.: Tub thumper, a presbyterian parson.
[UK]Lex. Balatronicum [as cit. 1785].
[UK]Egan Grose’s Classical Dict. of the Vulgar Tongue.
Glasgow Sentinel 3 Sept. 5/2: A considerable part of the ‘oration’ was a mere theological disquisition [...] with the clap-trap appeals usually employed by the lowest class of tub-thumpers.
[UK]M. Lemon Leyton Hall I 125: The fellow roared out some doggerel which expressd his supreme contempt for [...] Tubthumpers.
[UK] ‘’Arry on Pooty Women’ in Punch 21 Sept. in P. Marks (2006) 149: Don’t know, as the tub-thumpers spout, that the lion lies down with the lamb.
[UK]Ipswich Jrnl 15 Feb. 5/2: The Tub Thumper; Addresses to Working Men.
[Aus]Dead Bird (Sydney) 21 Dec. 2/4: ‘Come, oh, come and join me in the fold.’ exhorted an Evangelist of a fair young chorus lady hurrying by. ‘How long’ll it take?’ asked the good- humored girl. [...] But the tub-puncher had fled.
[UK]Shields Dly Gaz. 3 June 2/7: [headline] A Tory Tub Thumper.
[Aus]Truth (Sydney) 11 Mar. 1/2: Wesleyan parsons [...] are a set of bigoted, blatant, and brainless tub-thumpers.
[Aus]Bulletin (Sydney) 21 Dec. 22/2: He is the tub-thumper of whom Premier Jenkins remarked: ‘The hon. member is too suspicious to be politically honest, and too pious to be good.’.
[UK]Hangar Happenings Nov. 2: A very energetic assistant, whose argumentative powers would make a Hyde Park tub-thumper look silly.
[UK]W. Holtby Anderby Wold (1981) 247: And you’ll follow a hot-brained tub-thumper from Manchester, whose business it is to fool you left and right. Don’t you know he’s being paid to fool you?
[US]B. Schulberg Harder They Fall (1971) 52: You shouldn’t be a tub-thumper for a stable of fighters.
[US]Lait & Mortimer USA Confidential 52: Eleanor Roosevelt [...] is the chief tub-thumper for socialism.
[Aus]F.J. Hardy Outcasts of Foolgarah (1975) 81: He was [...] tub-thumper on the Domain.
R.H. Mason Photography Year Bk 235: A well known ‘tub thumper’ at Speakers’ Corner in Hyde Park.
[US]E. Behr Prohibition 179: This testy, foul-mouthed tub-thumper with a child’s attention span and only moderate intelligence.
[[UK]Guardian 17 Nov. 7: Straw thumps tub for speakers’ corner].
D.R. Obey Raising Hell for Justice 228: Huey [Long], had served as governor and US senator and had been a populist tub-thumper during the New Deal.

2. (UK tramp) a cooper.

[UK]Leamington Spa Courier 20 Sept. 7/1: There are a great many tramps staying in this district at the present time [...] We have among us [...] ‘tubthumpers’ (coopers) .