You Pronounce it: [in-vek-tiv]
1. vehement or violent denunciation, censure, or reproach.
2. a railing accusation; vituperation.
3. an insulting or abusive word or expression.
I found it:
While reading “Unladylike Polemics: Christine de Pizan’s Strategies of Attack and Defense” by Christine Moneera Laennec.
“The idea of characterizing de Pizan’s writing as invective, which becomes separated at times from its originary provocation, raises the question of the extent to which, in the texts, attack is not only necessary but also desirable” (Laennec 50)