Green’s Dictionary of Slang

thick n.

[SE thick]

1. any drink having a dense consistency, e.g. porter, cocoa, coffee.

[UK]M.E. Braddon Trail of the Serpent 183: The regulation coffee [...] commonly known to the inmates of the asylum as ‘the thick.’.
[UK]J.W. Horsley Jottings from Jail 26: Lads, your only friend here is your brown lofe and pint of thick.
[UK]Albert Chevalier ‘The God and The Star’ in Before I Forget (2009) 231–2: I’ve just left King Charles an’ Oliver Cromwell ’avin’ a cup o’ thick an’ a doorstep at the corfee stall.
[UK]O.C. Malvery Soul Market 152: Now then , miss, ’arf of thick, three doorsteps, and a two-eyed steak.
[UK]F. Jennings Tramping with Tramps 147: Rasher and fingers, a slab and a pint of thick!
[UK]E. Raymond Marsh 328: How could you do with a nice two-eyed steak, eh, and a couple ’a’ doorsteps, with a nice pint of thick to wash it all dahn with, eh?

2. (orig./mainly juv.) a fool, an ignoramus.

[UK]T. Hughes Tom Brown’s School-Days (1896) 127: I told you how it would be. What a thick I was to come!
[UK]Mansfield School-Life at Winchester College (1870) 238: Thick – Stupid [...] thus a Dunce.
[Ire]S. O’Casey Juno and the Paycock Act III: The thick made out the Will wrong.
[Ire](con. 1890s) S. O’Casey Pictures in the Hallway 10: With me landin’ first in Wicklow, an’ dhriven out again be th’ ignorant thicks.
[Ire]B. Behan Quare Fellow (1960) III i: Sure it’d only be a thick wouldn’t improve his knowledge when an older man would be willing to tell him something that would be of benefit to him in his career.
[UK](con. 1930s) D. Behan Teems of Times and Happy Returns 120: Yer an awful thick, Giggles.
[Ire]C. Brown Down All the Days 132: ‘How do you know?’ challenged another boy [...] ‘Didn’t I see it, you thick?’ declared Charley.
[Ire]H. Leonard Out After Dark 58: What the hell are you doing in Fourth Year, you thick, you?
[Ire]R. Doyle Van (1998) 386: The dog was no thick. He could nearly talk, the noises he made somethimes when he wanted a biscuit or a chip.
[Ire](con. 1916) R. Doyle A Star Called Henry (2000) 100: You thicks! You bloody eejits!

3. a thick slice of buttered bread.

[UK]G.R. Sims ‘The People’s Palace’ Dagonet Ditties 134: They made it a coffee palace, with scones and a plate of ‘thick.’.
[UK]G.R. Sims Off the Track in London 189: One of these, an eating-house, boldly announces itself as ‘Ye Olde Jimmy Thicks,’ and I take it that the ‘thicks’ are the slices of bread and butter.

4. (US black) one who has a muscular, well-developed physique.

[US]G. Smitherman Black Talk.

In phrases

fall in the thick (v.)

to become very drunk.

[UK]J. Ware Passing Eng. of the Victorian Era 127/1: Fall in the thick (Street). To become dead drunk. Full of metaphor. Black beer is called thick, so is mud; the phrase suggests equal misery whether the patient plunged in the mud, or ambled into drunkenness.