Green’s Dictionary of Slang

sugar n.2

1. a euph. for shit n. (1a)

[UK] ‘’Arry at a Political Pic-Nic’ in Punch 11 Oct. 180/1: Political Picnics mean sugar to them as is fly to wot’s wot.
[UK] ‘’Arry on a ’ouseboat’ in Punch 15 Aug. 76: And yet he will slate me like sugar, and give me cold beans with his charf.
[UK]G. Kersh Night and the City 269: I respect a man who can gamble sugar or bust on a few throws.
[US]J.H. Burns Lucifer with a Book 63: But this longhair stuff is just shit and sugar to me, see?
[US](con. 1945) G. Forbes Goodbye to Some (1963) 231: If the Aussies aren’t on Labuan . . . tough sugar for all of us.
[UK]J. McClure Snake 30: ‘Oh, shhh-sugar,’ he said.
[UK]J. Sullivan ‘Strained Relations’ Only Fools and Horses [TV script] Yeah, he’s as happy as a pig in sugar!
[UK]J. Morton Lowspeak.
Oxford American 1 July [Internet] Mitchell told Day that he was sure the record was a fiction. ‘I said, “Bullsugar,” ’Mitchell recalls [...] ‘Anyone that tells you they can beat the split screen is full of sugar.’ Mitchell tells me.

2. a contemptible person, a euph. for shit n. (2a)

[Ire]Joyce Portrait of the Artist as a Young Man 228: A flaming bloody sugar, that’s what he is!