Green’s Dictionary of Slang

to swear at, to curse (someone).

1777		Thrale Thraliana I May 28 47: Baretti [...] had also a Knowledge of the solemn Language and the gay; could be sublime with Johnson, or Black Guard with the Groom .
1792		H.H. Brackenridge Modern Chivalry (1937) Pt I Vol. I Bk III 40: These very clergymen, that put you forward to blackguard for them, will stand by laughing in their sleeves that you could be such a fool.
1813		P. Hawker Diary (1893) I 22 Feb. 69: We even remunerated the fellows that we blackguarded with beer.
1825		Chester Chron. 9 Sept. 4/5: Why, Sir, Jone’s mother blackguarded me sorely.
1836		D. Crockett in Meine Crockett Almanacks (1955) 52: I met a big fellow on the Levee at New Orleans, who [...] begun blackguarding me about my countrymen, for he didn’t belong to Kentucky himself.
1837		Caledonian Mercury 5 Oct. 4/2: Kitty— Didn’t you hear me blacggarding [sic] Billy Wallis? Pat Welch— No, be me oath, I din not.
1850		(con. 1843) Melville White-Jacket (1990) 240: ‘It’s this here Jonathan,’ answered Ringbolt; ‘he’s been blackguarding the young nob in the green coat, there.’.
1861		(con. 1840s–50s) H. Mayhew London Labour and London Poor II 482/2: Oh, sir, he was always blackgeyardin’ me. ‘Go back to your own counthry,’ says he.
1866		J. Greenwood Night in a Workhouse 38: They called him thief, sneak, and ‘crawler.’ Little boys blackguarded him in gutter language.
1878		F.H. Hart Sazerac Lying Club 108: These here office-seeking cusses can stand all the blackguardin’ you’ve a mind to give ’em; you can abuse ’em all you want.
1889		Salt Lake Herald (UT) 19 Feb. 4/2: There will be no bloodshed over the name-calling and blackguarding of each other in which certain memebers [...] are now engaged.
1894		Salt Lake Herald (UT) 29 Jan. 2/2: The Herald is accused by the Tribune of blackguarding in the grossest manner the Republican members.
1900		Bulletin (Sydney) 1 Sept. 11/3: I yesterday found the two youngsters squatting upon a pile of horse-feed, and, in many bad English words, black-guarding the stableboy.
1905		St Louis Republican (Sun. Mag.) 25 June 8/1: They said: ‘Wah! Wah! Wah! [...] and it was nothing else than cursing and blackguarding. How these monkeys did hate us’ .
1916		Pickens Sentinel (SC) 30 Mar. 4/1: Think what a ‘bully’ time Teddy [Roosevelt] will have blackguarding the other candidates!
1929		J. Sale Tree Named John 135: He wuz a-cussin’ en a-blackgyardin’ ’em all de time.
1933		J. Conroy Disinherited 185: Don’t like to hear such bla’guardin’ about a good Christian woman.
1946		R. Grinstead They Dug a Hole 8: In the Brigade of Guards [...] we have a language of our own, referring to this harmless, if at times extremely irritating, practice of ‘blackguarding’, or ‘taking the piss out of’ one’s fellows.