nobbler

noun

1. A person who interferes with a racehorse or greyhound in order to prevent it from winning a race.
2. (Australia, obsolete)A serving of beer or spirits.

   “1874, [John Brady], The McIvor Times and Rodney Advertiser (Heathcote, Vic. : 1863 - 1918) Thursday 24 December 1874 Coroner's Inquest http://trove.nla.gov.au/ndp/del/article/89693062#pstart8412354 - 12-year-old witness to road accident death of his father, ‘My father only had two nobblers at Dwyer's place that morning.’”

   “1895, Guy Boothby, A Bid for Fortune, ReadHowYouWant, 2008 EasyRead Comfort Edition, page 266, ‘A nobbler o′ rum,’ says I. Then he orders a nobbler of rum for me and a nobbler of whisky for ′imself.”

   “‘Fer goodness′ sake, Doreen! Give the gent a nobbler of brandy and stop making trouble.’ It′s the little weasel bloke what speaks. ‘Much obliged,’ I says to him. ‘Nobbler, is it?’ Doreen turns on her heel and she′s about to vanish into the main bar when I shouts after her, ‘Nobbler of Cape, miss!’”

   “This done, he waves his hat and declares his nag can lick anything on the ground—for nobblers round.”

3. (UK, obsolete)A thimbleman's or cardsharp's accomplice or shill, who poses as a player of the game to suggest that it is easy to win.