Green’s Dictionary of Slang

cock n.5

[SE cock and bull story but note cook up v. (2) + the Cock Lane ghost, ‘which had a great run, and was a rich harvest to the running stationers’ (Hotten, 1867)]

1. a broadsheet or pamphlet, sold in the streets and relating some form of lurid and sensational incident, typically a fire, a murder or an accident.

[UK]Hotten Dict. of Modern Sl. etc. 22: Cocks fictitious narratives, in verse or prose, of murders, fires, and terrible accidents, sold in the streets as true accounts. The man who hawks them, a patterer, often changes the scene of the awful event to suit the taste of the neighbourhood he is trying to delude. Possibly a corruption of cook, a cooked statement.
[UK](con. 1840s–50s) H. Mayhew London Labour and London Poor I 214/2: ‘Cocks;’ which, in polite language, means accounts of fabulous duels between ladies of fashion – of apochryphal elopements, or fictious love-letters of sporting noblemen [...] or awful tragedies, including mendacious murders, impossible robberies, and delusive suicides.
[UK]C. Hindley Curiosities of Street Lit. n.p.: With these remarks we now introduce our readers to a genuine Catnachian ‘Cock’ [...] entitled ‘Horrid Murder Committed by a Young Man on a Young Woman’.
[UK] in Sl. Dict. 121: A ‘cock’ is an apocryphal story, generally, of a murder or elopement bawled about the streets by the Seven Dials’ ‘patterers’.

2. nonsense, rubbish; also in phr. (load of) old cock.

implied in talk cock
[UK]J. Maclaren-Ross ‘Phantom of the Cookhouse’ in Bitten by the Tarantula (2005) 173: Well, if you arst me, sir, it’s a lot of cock.
[UK]C. MacInnes Absolute Beginners 39: If they think that all cat’s c—k, well, let them think it and good luck!
[Aus]D. Niland Pairs and Loners 164: Ah, cut out the cock and hand it over.
[Aus]D. Ireland Glass Canoe (1982) 199: I never fell for that sort of cock when I was a kid.
[UK](con. 1940s) O. Manning Danger Tree 131: To say that Hitler can’t be beat / Is just a lot of cock.
[Aus]G. Seal Lingo 66: Other well-used World War II complaints still in wide use today included [...] to be jack of something, possibly everything, and a lot of (hot) cock used to describe anything felt to be nonsense.

In compounds

cock-catch (v.) [orig. milit. use]

to obtain money on false pretences.

[UK]J. Ware Passing Eng. of the Victorian Era 67/1: Catch Cocks, To (Low Military). To obtain money by false pretences. Catch-cocks are contrived by characterless soldiers who address gentlemen, invent tales of distress, and often thereby obtain money. ‘Joe, let’s go cock-catching.’.

In phrases

all to cock (adj.)

unsatisfactory, mixed up, useless.

[UK]K. Amis letter 2 Dec. in Leader (2000) 102: I am not printing these words because the ribbon on my printer is all 2 cock and shagged 8.
[UK]P. Larkin letter 7 May in Thwaite Sel. Letters (1992) 274: The rhyme’s all to cock otherwise. I’m sure it’s far too late to do anything about it now.
[UK]A. Ayckbourn Ten Times Table I iii: The kennels are all to cock.
B. Lumley House of Doors 21: My system’s all to cock.
C. Heylin Bootleg 241: The volume level is all to cock.
hot cock (n.)

(Aus./US) nonsense, rubbish.

[Aus]R. Rivett Behind Bamboo 396/2: Hot cock, nonsense, boasting, vain talk.
[US]D. Howard ‘USMC Sl.’ AS XXXI:3 193: hot cock, n. News.
[Aus]G. Seal Lingo 66: Other well-used World War II complaints still in wide use today included [...] to be jack of something, possibly everything, and a lot of (hot) cock used to describe anything felt to be nonsense.
talk cock (v.) [sense 2 above; although the assumed link is to cock n.3 (1)]

to talk nonsense.

C. Day Lewis Starting Point iii 52: ‘If I hadn’t let Mackenzie through that time, we’d have won.’ ‘Don’t talk cock. You played a damned good game.’ .
[UK]Partridge DSUE (8th edn) 232: [...] since ca. 1938.