Vipaccatā (feminine) at Vin II 88 is perhaps a derivation from vi + vac, and not pac, thus representing a Sanskrit vivācyatā, meaning "challenging in disputation," quarrelsomeness, provocation. See also vipāceti. If from vi + pac, the meaning would be something like "heatedness, exasperation."
(fem, fem, abstr, from vivaccati) heated speech; quarrelsome talk heated speech; quarrelsome talk Construction: vi + pacca + tā