Green’s Dictionary of Slang

white-choker n.

also white chokered ’un
[the white bands that are part of his dress]

a clergyman; also attrib.; thus white-chokerite, white-chokered.

[Aus]Bell’s Life in Sydney 8 June 3/3: A great depression was observed amongst the Saints, Field preachers, and white chokered-uns.
[Aus]Bell’s Life in Victoria (Melbourne) 18 Apr. 2/4: Whatever antiquated notions certain white-chokerites may indulge in, the worthy Master of the Melbourne Hunt saw no sin in a calling a muster of his sporting friends on a day ranking specially holy in calendar.
[UK]Hotten Dict. of Modern Sl. etc.
[Scot]Glasgow Herald 31 May 6/1: The clergy are bricks, depend upon it [...] A good deal of excitement and unadulerated fun are to be found in the great white choker gatherings in Edinburgh.
[UK]Sl. Dict. 117: Clergymen and Exeter Hallites are frequently termed white-chokers.
[UK] ‘’Arry on ’Igh Life’ in Punch 20 July 24: Men o’ the world [...] / Ain’t precisely the species of bird to be caught by such white-choker chaff.
[UK]London Life 16 Aug. 2/1: [headline] white-chokered hypocrites.
[Aus]Melbourne Punch 12 Jan. 8/2: The white chokers ought to get up in their pulpits and forbid the use of the cruel cat-’o-nine-tails.
[UK]Illus. Police News 15 July 4/1: Stow any white-choker patter.
[Aus]Crowe Aus. Sl. Dict. 17: [W]hite choker, a parson.
[US]A.H. Lewis Boss 264: The w’itechoker, who passes me on to you, gets his lamps on me an’ begs me off from d’ judge.

In derivatives