Green’s Dictionary of Slang

1. ingratiating, unctuous, smoothly insincere [? originated in the nickname ‘Soapy Sam’, used of Bishop Wilberforce (1805–73)].

1843		R.S. Surtees Handley Cross (1854) 250: It may be well to commence in the soapy line.
1854		E. Twisleton letter 22 June in Letters to Her Family (1928) 202: The Bishop of Oxford I never do like [...] his manner, when Lords are in presence, richly merits his popular sobriquet of ‘Soapy Sam’ .
1865		Pall Mall Gazette 28 Oct. 5: But why [...] do people call him [Bp. Wilberforce] Soapy Sam?
1878		‘’Arry on Pooty Women’ in Punch 21 Sept. in P. Marks (2006) 149: I ’ave heard soapy sneakers protest, and declare the whole thing infry dig.
1885		Bulletin (Sydney) 3 Oct. 11/2: Hitherto we were indefinite on the point, and had we been asked the essentials [of a parson] would have given them as (in many cases) – No. 1, look soapy and hump a plate; and No. 2, hump a plate and look soapy.
1897		J. Buchan Moon Endureth (2004) 48: He had once been famous for his soapy manners: now he was as rough as a Highland stot.
1897		Bendigo Indep. (Vic.) 23 Jan. 3/1: Plausible soapy old fellows who were past masters in the art of palavering the women .
1908		Magnet 7 Mar. 9: Be a little less of a soapy rotter.
1912		P.C. Wren Dew & Mildew 199: Soldiers detested him [i.e. a missionary] [...] Soapy Sammle was the only printable term of endearment they applied to him.
1922		Joyce Ulysses 435: A plagiarist. A soapy sneak masquerading as a literateur.
1938		H. Asbury Sucker’s Progress 61: Soapy Smith was the king-pin of them all [i.e. confidence tricksters].
1977		G.F. Newman A Prisoner’s Tale 20: Bathing [...] was [...] a weekly occurence, and some of the soapy bastards even avoided it then.
1987		J. Ciardi Good Words 265: Soapy Sam. A generalized disparaging nickname for any unctuous person [...] In common Am. use until about WWII.
2000		J.J. Connolly Layer Cake 164: ‘Not eatin, lads?’ says the soapy geezer behind the ramp. ‘Why not ’ave a bitta cake.’.

2. (Aus.) foolish, silly, effeminate.

1880		Freeman’s Jrnl (Sydney) 24 Apr. 5/1: ‘He is a soapy fellow, and if you lay it on thick you may possibly save both the expense and exposure’ .
1941		Baker Popular Dict. Aus. Sl.
1945		Mail (Adelaide) 4 Aug. 2/6: ‘No,’ said Jonothan. ‘Don’t be soapy. You don’t want them’ .
1955		N. Pulliam I Travelled a Lonely Land (1957) 239/1: soapy – silly, affected.
1968		J. Alard He who Shoots Last 112: Who is this soapy-looking bird, Sergeant?
1977		G.F. Newman Villain’s Tale 28: His blond hair was fairly long, but Lynn was prepared to tolerate that, for it was meticulously styled – hair hanging in rats’ tails like some of the soapy bastards wore it was what he couldn’t stand.
1985		R.G. Barrett You Wouldn’t Be Dead for Quids (1989) 32: Three soapy bikies and their scruffy frump of a girlfriend.
1991		R.G. Barrett Between the Devlin 46: His tenants or what he’d seen of them so far, were a soapy-looking lot to say the least.

3. typical of family and social life as portrayed in radio and TV drama series [soap opera n.].

1999		Guardian Rev. 12 June 8: The unfolding soapy psychodrama of ‘Will Nathan tell Mary he is her father?’.
2000		Guardian Editor 21 Jan. 17: This [...] ‘soapy account of a depressing London family’.