Green’s Dictionary of Slang

1. (also buff it home) to brazen out.

1748–49		Cleland Memoirs of a Woman of Pleasure (1985) 49: As knowing as she was of the town, as hackney’d as she was in buffing through all the dangers of her vocation.
1799		Aurora (Phila.) 23 Aug. n.p.: If we were as fond of fighting France as ever buffing Jackson, or big Ben, or the tinker of Cornwall were of entering the lists.
1830		Lytton Paul Clifford III 126: Tell me, do you think the Grazier will buff it home?
1838		Paul Pry 30 Sept. 180/2: We know all about his racing establishment at Stockwell [...] and how he buffed it before the late committee.
1881		Trumble Sl. Dict. n.p.: Buffing it home is swearing point-blank to anything, about the same as bluffing it, making a bold stand on no backing [F&H].
1895		Crowe Aus. Sl. Dict. 12: Buffing it Home, same as bluffing it; swearing point blank to anything.

2. to give evidence, to testify.

1811		Lex. Balatronicum n.p.: buff. [...] To swear as a witness. He buffed it home; and I was served; he swore hard against me, and I was found guilty.
1821		Egan Life in London (1869) 222: One of the coffee-shop party is tipping a Charley to buff it strong against tom and jerry.
1833		‘The City Youth’ in Out-and-Outer in Spedding & Watt (eds) Bawdy Songbooks (2011) IV 140: The traps they buff it home the forty for to chop.
1848		Ladies’ Repository (N.Y.) Oct. VIII:37 316/1: Buff to, to swear to or against. Buff for, to swear in favor.
1852		Bell’s Life in Sydney 7 Feb. 2/7: He requested the policeman not to buff too strongly against him [...] ‘I am afraid you will cook my goose’.
1859		Hotten Dict. of Modern Sl. etc. 12: BUFF, to swear to, or accuse.
1867		H.L. Williams Ticket-of-Leave Man 12: I’d as leaf have murder as a crack ‘buffed’ to me.
1870		Hotten Sl. Dict. [as cit. 1859].
1896		M. Williams Round London 96: What robberies are you going to buff me for?

3. to commit perjury, to swear falsely.

a.1790		H.T. Potter New Dict. Cant (1795).
1797		‘T.B. Junr.’ Pettyfogger Dramatized I i: He has buffed at least one thousand in my service.
1809		G. Andrewes Dict. Sl. and Cant.
1821		Flash Dict.
1835		G. Kent Modern Flash Dict. 7: Buff, to – to swear falsely, to perjure.
1848		Flash Dict. in Sinks of London Laid Open [as cit. 1835].
c.1850		Duncombe New and Improved Flash Dict.
1869		Mt Alexander Mail (Vic.) 28 Oct. 3/3: A man [...] would stato that he had been in possession of tho jewellery, and had; sold it in the open market. The consequence would most probably be that the prisoners would be discharged, there being no evidence of the property having been stolen. The species of fraud was what was known by the slang term ‘buffing’.

4. to inform against.

1859

Hotten Dict. of Modern Sl. etc. 12: BUFF, [...] to peach upon.

5. (US drugs) to manipulate, to con, to threaten.

1997

L. Pettiway Workin’ It 135: They lose all morals, principles and respect [...] You know, buff somebody, buff the dude – suck somebody dick. Buffing up them guns. People have said they children are in hospital, all that kind of shit ... they mother died. People do that shit for hits.