Invective
Invective (noun), from Middle English invectif, or Old French and Late Latin invectus, is an abusive, reproachful or venomous language used to express blame or censure; also, a rude expression or discourse intended to offend or hurt. Vituperation, or deeply seated ill will, vitriol. Also note: Latin invectivus (adj.), 'scolding.'
The genre of invective
The "genre of invective" or "invective (genre)" is a form of classical libel used in Greek and Roman polemical verse. The preferred literary term for invective of the Renaissance is libel.
See also
Libel (poetry)
References
Farlex Free Dictionary, "in·vec·tive"
Princeton University, Farlex Inc. 2003-2008: "in·vec·tive (n-vktv)"
The American Heritage Dictionary of the English Language, Fourth Edition copyright ©2000 by Houghton Mifflin Company, 2003: "in·vec·tive"
Collins Essential English Dictionary, HarperCollins Publishers 2004, 2006