• (British) IPA: /ˈblæɡəd/
• (America) IPA: /ˈblæɡɚd/

blackguard (plural blackguards)

1. (old-fashioned, usually used only of men) A scoundrel; an unprincipled contemptible person; an untrustworthy person.
   • 1830, Thomas Macaulay, Review of Robert Southey's edition of Pilgrim's Progress, in the Edinburgh Review

     A man whose manners and sentiments are decidedly below those of his class deserves to be called a blackguard.}}

   • 1899, Knut Hamsun, “Part I”, in George Egerton [pseudonym; Mary Chavelita Dunne Bright], transl., Hunger: Translated from the Norwegian, London: Leonard Smithers and Co. […], OCLC 560168646 ↗; republished New York, N.Y.: Alfred A. Knopf, October 1920 (December 1920 printing), OCLC 189563 ↗, page 58 ↗:

     Pawn another man's property for the sake of a meal, eat and drink one's self to perdition, brand one's soul with the first little sear, set the first black mark against one's honour, call one's self a blackguard to one's own face, and needs must cast one's eyes down before one's self? Never! never!

   • 2006, Jan Freeman, 'Blaggards' of the year – Boston Globe ↗

     "Arrr, keelhaul the blaggards!" wrote Ty Burr in the Globe last summer, pronouncing sentence on the malefactors who brought us the second "Pirates of the Caribbean" movie.

2. (archaic) A man who uses foul language in front of a woman, typically a woman of high standing in society.

blackguard (blackguards, present participle blackguarding; past and past participle blackguarded)

1. (transitive) To revile or abuse in scurrilous language.
2. (intransitive) To act like a blackguard; to be a scoundrel.