Green’s Dictionary of Slang

1. to cheat.

1832		Satirist (London) 13 May 159/1: They are paid a weekly sum, generally about £2; [...] and the money given them to bonnet (that is, to play) with, is always stamped by Leaming with a private mark, to prevent any welling.
1843		Dickens Christmas Carol (1868) 22: Scrooge reverently disclaimed... any knowledge of having willfully ‘bonneted’ the Spirit at any period of his life.
1847		Bell’s Life in Sydney 24 Apr. 3/4: I’ll be bound they’ll never bonnet me again.
1868		Sportsman 2 July 2/1: Notes on News [...] [T]he Rev. John Lester, D.D., is certainly fine a specimen of ‘bonneting up’ as ever appeared.
1873		J. O’Connor Wanderings of a Vagabond 322: A dozen or more banks in the city carried on their business without fear of molestation. Their dealers were neither ‘bonneted’ nor robbed, nor in any respect disturbed at their business.
1887		W.E. Henley ‘Villon’s Straight Tip’ in Farmer Musa Pedestris (1896) 176: Bonnet, or tout, or mump and gag; / Rattle the tats, or mark the spot.
1889		Clarkson & Richardson Police! 223: All persons possessed of valuables are roughly handled; they are ‘bonneted,’ robbed of money, watch and chain, rings, pins.

2. to boost a price, e.g. of odds bet on a horse or the sale price of an item on which one receives commission.

1848		‘Epistle from Joe Muggins’s Dog’ in Era (London) 29 Oct. 3/3: They had bonnetted up ther big Hirish Himposter to 3 to 1.
1851		‘Epistle from Joe Muggins’s Dog’ in Era (London) 16 Feb. 4/2: You've seen how shaky Grecian haz been lately, spite of ther bonnettin up ov hiz party, and all ther gaffin aboute stakin and kallin to kover.
1860		R. Nicholson Rogue’s Progress (1966) 81: Why, after bonneting, and getting five pounds for you out of that flat do you think I’m such a fool as to allow you to take the box, and play against the bank?
1873		Sl. Dict. 91: A man who persuades another to buy an article on which he receives commission or per-centage is said to bonnet or bear-up for the seller.
1882		Sydney Sl. Dict. (2 edn) 2: Chuck a Jolly - To ‘bonnet,’ to praise an article a mate is trying to sell; sometimes, to banter.

3. to pull or crush a person’s hat over their eyes, thus temporarily blinding them; thus bonneting n.

1828		G. Smeeton Doings in London 68: Every operator of this game is attended by certain friends called eggers and bonnetters [...] the bonnetters, to bonnet any green one who may happen to win – that is, knock his hat over his eyes, whilst the operator and the others bolt with the stakes.
1838		R. Nicholson Cockney Adventures 24 Feb. 131: ‘Bonnet ’em,’ said a slim young man, who appeared to rejoice in the cognomen of Weasel.
1846		Bell’s Life in Sydney 8 Aug. 3/3: The wretched lobster was initiated into the mysteries of ‘bonnetting,’ one of the fellows having seized him by the collar while Emms perpetrated the horrid enormity of imprisoning the poor trap's phiz in his own shako!
1849		Sam Sly 3 Mar. 1/1: [A] decent-looking man [...] who was speedily bonnetted and kicked out.
1859		G.A. Sala Twice Round the Clock 118: The buffeting of his wretched ears, the upripping of his unhappy coat-collar [...] the ‘bonneting,’ the ‘ballooning,’ and the generally fiendish cruelties.
1866		Wild Boys of London I 128/1: ‘Bonnet ’em!’ roared the Dolphin, and suiting the action to the word, he skilfully sent the peeler’s hat over his eyes.
1868		Greenock Teleg. 24 July 3/2: Mr Street [...] made himself so conspicuous in hissing Mr Christie [...] as to get a deserved bonneting for his pains.
1869		Man about Town 16 Oct. 43/3: [A] meagre set of decrepid creatures [...] who were wont to bear bonneting bravely and chaff cheerily.
1877		A. Smith Street Life in London (1969) 45: He was irrepressible in the matter of bonneting the police.
1880		Bulletin (Sydney) 17 Apr. 3/3: Mr. Thomas Alcock, the well-known tanner, ‘bonnetted’ John M’Elhone [...] the other day by way of a joke. John didn’t hit him back [...] but he straightway took out a summons and had it served before the ‘ bonneter ’ left the place.
1887		‘’Arry on Law and Order’ in Punch 26 Nov. 249/2: To bonnet a load of old blokes and make petticoats squeal is good biz.
1895		Crowe Aus. Sl. Dict. 11: Bonnet Him, to knock his hat over his eyes.
1898		Binstead & Wells Pink ’Un and Pelican 282: Playfully bonneting the old man with his own beaver, and rolling him over in the deserted and dusty passage.
1900		Bulletin (Sydney) 3 Feb. 14/3: Again, in Riverina there was a ‘bodiless woman’ showing, and a gang of youthful pastoralists bonneted the doorkeeper, rushed the stage, smashed up all the ‘fakes,’ and scooted.
1903		E.W. Townsend ‘Chimmie Fadden Stories’ 8 Nov. [synd. col.] ‘If he doesn’t get a quick gait out of here I’ll bonnet him’.
1910		Wodehouse Psmith in the City (1993) 130: The hooligan who bonnets a policeman is apparently the victim of a sudden impulse.
1916		‘Anzac’ On the Anzac Trail 35: [of a collapsing tent] Once I saw a pole go clean through the top of a tent, the canvas, of course, sliding down like a parachute and ‘bonneting’ the inmates.
1938		H. Asbury Sucker’s Progress 187: A dealer was robbed by a method known as ‘bonneting’ — that is, a group of rowdies would fling a blanket over his head, and [...] make off with his chips and whatever money happened to be in the card box.