Q. 1. What is the heresy of "Semipelagianism?"
A. 1. The heresy of "Semipelagianism" was a rejection of the heresy of Pelagianism which held that Augustine had gone too far to the other extreme and taught that grace aided the free will rather than replacing it.
The aforementioned views were promoted by Prosper and Hilary of Aquitaine, John Cassian and Vincent of Lérins in the west.
Semipelagianism was condemned by the Council of Orange in 529 which slightly weakened some of Augustine's more extreme statements.
It should be noted that the term "Semipelagianism" originated in the seventeenth century.