Green’s Dictionary of Slang

thick as... adj.

1. stupid; used in a variety of combs., for the best-known of which see below.

[UK]Shakespeare Henry IV Pt 2 II iv: He’s a good wit? Hang him, baboon! His wit is as thick as Tewksbury mustard.
[US]T. Haliburton Sam Slick in England II 36: Then tell me if rich people here ain’t as thick as huckleberries.
[US]J.T. Farrell Gas-House McGinty 42: The Old Man is as thick as dough.
[UK]C. Wood ‘Prisoner and Escort’ Cockade (1965) I iii: Beezed up and buffed up like a camp of thick as shit guardsmen.
[UK]P. Terson Apprentices (1970) I iii: He’s joining the pioneers. He’s as thick as a shovel.
[US]G.V. Higgins Rat on Fire (1982) 15: The nuns down Our Lady of Victory practically made a public announcement [...] that Leo Proctor was thick as shit.
P. Nevin Ireland 87: Everyone around said that Charley Reilly was ‘as thick as a ditch’.
[UK]J. Healy Grass Arena (1990) 8: You’re as thick as Conner’s ass.
[Ire]J. O’Connor Salesman 242: Bit like yerself that way. Thick as a bucket of shite. [Ibid.] 299: Big stupid-lookin’ black and white thing, he was [...] Thick as a brick.
[UK]Guardian Guide 1–6 Jan. 23: All-dancing school-room hit Thick As A Brick.
[Ire]G. Coughlan Everyday Eng. and Sl. [Internet] Thick as a ditch (phr): really stupid person.
[Aus]T. Winton ‘Big World’ in Turning (2005) 11: Meg is as thick as a box of hammers.
P. Cockburn Broken Boy 34: She thought he was ‘as thick as the wall’.
T. Carrington et al. One-Click Buy 7: A girl would have to be thick as a ditch to walk away from that.
[US]J. Díaz This Is How You Lose Her 100: Fresh-off-the-boat-didn’t-have-no-papers Dominican. And thick as fucking shit.

2. very close, extremely intimate; used in a variety of combs., for the best-known of which see below.

in ...thieves
[US]Lewisburg Chron. (PA) 4 Jan. 7/3: Lawyers and printers are thick as fleas.
[UK]Sporting Times 1 Apr. 11/2: There were once two nice boys who both became as thick as treacle with a dear little soul.
[US]F. Hutchison Philosophy of Johnny the Gent 5: One day they’ll be tellin’ everybody what a hunk o’ cheese the other guy is, an’ the next time you see ’em they're thicker’n Rubes around a big six wheel.
[US] in J.F. Dobie Rainbow in Morning 90: As thick as hops; as thick as my foot; as thick as the hairs on a dog’s back (expression of quantity).
[US]T.J. Farr ‘The Language of the Tennessee Mountain Regions’ in AS XIV:2 92: thick as two in a basket. Very friendly or intimate.
[US]S. Longstreet Flesh Peddlers (1964) 265: Thick as fleas, the two of them.
[US]M. Spillane Return of the Hood 41: He and Penny Stipetto were thick as blood brothers.
[UK]R. Barnard Death in a Cold Climate (1991) 63: ‘Is that a close little group?’ [...] ‘Course some of them stick together thick as flies on a bull’s arse.’.
[Aus]R.G. Barrett White Shoes 258: Him and KK are as thick as pig shit; they’re always pissing off together.

3. (US) extremely plentiful; used in a variety of combs., for the best-known of which see below.

in ...flies round a treacle pot
[US]Colored American (DC) 7 Nov. 14/1: Jackled Negro lawyers are as thick as ‘bees’ in Washington, but they are harmless.
[[US]S.E. White Arizona Nights 113: In ten minutes I had more friends in Cyanide than they is fiddlers in hell].
[US]G.A. England ‘Rural Locutions of Maine and Northern New Hampshire’ in DN IV:ii 72: fiddlers in Hell, thick as, adj. phr. Very plentiful.

In phrases

...flies round a treacle pot (also ...flies in treacle, ...flies on a lump of sugar)

plentiful, numerous.

[UK]Bucks Herald 26 Jan. 4/5: The spectators around them were thick as flies on a lump of sugar.
E. Pugh City of The World 271: Them there big railway stations where there’s splits all over the shop as thick as flies round a treacle pot.
[UK]Nottingham Eve. Post 13 Dec. 5/2: Compare this with the fortunate people whose holidays seem to be as thick as flies in treacle.
[UK]Western Morn. News 13 Mar. 3/5: ‘The Spitfires were as thick as flies around sugar,’ declared an American.

very stupid.

[UK](con. 1950s) D. Nobbs Second From Last in the Sack Race 268: I’m as thick as pig shit.
[Ire](con. 1970) G. Moxley Danti-Dan in McGuinness Dazzling Dark (1996) II iii: Thick as pig-shit plaited the pair of us.
[UK]Guardian Guide 14–20 Aug. 28: Wholly predictable in every thick-as-pigshit way.
[Aus]G. Seal Lingo 88: Bodily and mental afflictions, real, imagined or fervently wished, also feature strongly in Lingo. One can be [...] lame as a mule; thick as two short planks; thick as pig shit; queer as a beer; camp as a row of tents.
[UK]J.J. Connolly Layer Cake 71: What they’ve got instead [of children] is two thick-as-pig-shit Dobermans.
[UK]N. Griffiths Stump 59: Thick as shite, are’t yeh? Thick as fuckin pigshit.
...poundies [Irish poundies, mashed potato mixed with onion and milk]

(Irish) very stupid .

[Ire]Share Slanguage.
...thieves (also ...two thieves)

very intimate.

[[UK]T. Jordan ‘The Cheaters Cheated’ in A Royal Arbor 38: Cham come to zee my Lord Major, / And thick as do hang the thieves, / Ch’ve fordgot what vine neames they are, / (A meaxle on them) the zhreeves].
M. Reid Osceola I80: One of them the very keenest of his executioners, and all four now apparently as thick as thieves!
[UK]Western Times 19 Aug. 2/5: The tories, to use a homely phrase, are ‘as thick as thieves’.
[UK]New Monthly Mag. III 149: Her mistress and she are as thick as thieves.
[UK]R. Nicholson Cockney Adventures 10 Feb. 117: Didn’t I see you all talking with him as thick as thieves?
[US]T. Haliburton Clockmaker III 223: King and me would be as thick as two thieves.
[US]T. Haliburton Sam Slick’s Wise Saws II 90: We were as thick as two thieves.
[UK]Punch 6 Dec. 222/1: There warnt none o’ your silent and separate games then; — it was thick as thieves you may say, and hevery opper-tewnity for the old ands to put the younguns hup to hevery Iark they knowed theirselves.
[UK]Whitstable Times 18 May 3/4: Why, I thought you were as thick as thieves.
[US]W.H. Thomes Bushrangers 319: I’se seen ’em as thick as two thieves at Smith’s.
[US](con. c.1840) ‘Mark Twain’ Huckleberry Finn (2001) 264: In about a half an hour they was as thick as thieves again.
[US]E. Townsend Chimmie Fadden Explains 96: Just get tick as two tieves and spoon a little.
[UK]G.F. Northall Warwickshire Word-Book 238: Thick. Intimate. ‘As thick as thieves.’.
[Aus]J. Furphy Such is Life 5: I’ll slip over in two minits on Valiparaiser, an’ consult with Alf. Me an’ him’s as thick as thieves.
[US]H.L. Wilson Ruggles of Red Gap (1917) 320: The four began to be as thick as thieves.
[UK]P. O’Donnell Islanders (1933) 156: Biddy Melly tells me him an’ our Susie’s as thick as thieves.
[US]W.M. Raine Cool Customer 266: You and he are thick as thieves.
[Aus]K. Tennant Battlers 164: Postle’s fick as fieves wiv all them Littles. ’E sits and yarns to ’em all the bloody day.
[UK]A. Buckeridge Jennings Goes To School 168: As thick as thieves, sir?
[UK](con. 1920s) D. Holman-Hunt My Grandmothers and I (1987) 148: He and Dan are as thick as thieves.
[UK]S. Berkoff East in Decadence and Other Plays (1985) 51: The two of us got thick as tea leaves.
[US]R. Campbell Sweet La-La Land (1999) 183: They was thick as thieves fifteen, sixteen years ago.
[UK]K. Sampson Awaydays 19: Michael Reilly and I are to become thick as thieves during my two-and-a-bit years at the Johnny’s.
...three in a bed

very intimate.

[UK]W. Scott Monastery Introductory Epistle n.p.: That’s right, Captain, [...] you twa will be as thick as three in a bed an ance ye forgather .
[UK]Exeter & Plymouth Gaz. 1 Dec. 2/1: The silk gowns at the King’s Bench bar are, as Mr Fox said [...] ‘as thick as three in a bed’.
[UK]Leicester Jrnl 2 Dec. 1: ‘As thick as three in a bed’ has long been illustrative of too many in the sleeping department.
[US]N.Y. Daily Trib. 16 Oct. 2/6: [headline] Thick as Three in a Bed.
Preston Chronicle 25 Jan. 3/6: He could at least say that they were ‘thick’ — ‘as thick as three in a bed’.
[US]F. St. Clair Six Days in the Metropolis 7: ‘Full as a tick, ma’am,’ said a man [...] ‘We’re as thick as three in a bed,’ added another.
N. Wales Chronicle 8 Oct. 6/7: One log cabin was erected first, in which both families lived ‘thick as three in a bed’.
[US]P.G. Brewster ‘Folk “Sayings” From Indiana’ in AS XIV:4 267: Persons who are very intimate are ‘as thick as three in a bed.’.
...two inkle-weavers (also …inkle-weavers, ...two inkle-makers, as great as two inkle-weavers) [SE inkle, linen tape]

very close .

[UK]B.E. Dict. Canting Crew n.p.: As great as two Inkle-makers, or as great as Cup and Cann.
[UK]New Canting Dict. [as cit. c.1698].
[UK]Swift Polite Conversation 48: Why she and you were as great as two Inkle-Weavers. I am sure, I have seen her hug you, as the Devil hugg’d the Witch.
[UK]Grose Classical Dict. of the Vulgar Tongue n.p.: Inkle weavers, supposed to be a very brotherly set of people; ‘as great as two inkle weavers’ being a proverbial saying.
[UK]Lex. Balatronicum [as cit. 1785].
[UK](con. early 17C) W. Scott Fortunes of Nigel II 280: We had a carouse to your honour [...] we were as loving as inkle-weavers.
[UK]‘Jon Bee’ Dict. of the Turf, the Ring, the Chase, etc.
[UK]W. Carr Dialect of Craven II 198: Thick. Intimate, familiar. ‘As thick as Inckle weavers,’ who, Grose observes, are a very brotherly set of people.
...two short planks (also ...a plank, ...eight short planks, …ten short planks, …two bricks, …two planks)

very stupid.

[UK]Clement & La Frenais ‘New Faces, Old Hands’ Porridge [TV script] Three years, robbery third stretch. Thick as two short planks.
[Ire]H. Leonard Time Was (1981) Act II: You’re right. As thick as two planks.
[UK]A. Payne ‘All Mod Cons’ in Minder [TV script] 40: I’m thick as two short planks, generous when it suits me.
[UK]S. May No Exceptions in Best Radio Plays (1984) 120: Come off it, Bill, he’s as thick as eight short planks.
[Aus]R. Beckett Dinkum Aussie Dict. 9: All blues [i.e. blue heelers] are regarded by their owners as being ‘as thick as two bricks.’.
[UK]R. Barnard A Fatal Attachment (1993) 180: ‘Thick?’ ‘Two planks.’.
[UK]Observer 18 July 10: Thin as a rake and thick as a plank.
[Aus]G. Seal Lingo 88: Bodily and mental afflictions, real, imagined or fervently wished, also feature strongly in Lingo. One can be [...] lame as a mule; thick as two short planks; thick as pig shit; queer as a beer; camp as a row of tents.
J. White in Carter Anthony Blunt (2002) 389: Moderately handsome, but not that handsome — the latest boyfriend, and thick as two short planks.
[UK]B. Hare Urban Grimshaw 4: Tyson [i.e. a dog] was [...] as thick as ten short planks.
[UK] (ref. to 1971) F. Dennis ‘Old Bailey’ Homeless in my Heart 183: And trusties shuffle and mutter [...] Where screws are as thick as a plank.
[Aus]J.J. DeCeglie Drawing Dead [ebook] She’s a real criminal mastermind this one. Thicker than two planks it would seem.