horrific (adj.)

"causing horror," 1650s, from French horrifique or directly from Latin horrificus "dreadful, exciting terror," literally "making the hair stand on end," from horrere "be terrified, bristle, to stand on end" (see horror) + -ficus "making, doing," from combining form of facere "to make, to do" (from PIE root *dhe- "to set, put"). An older adjective was horriferous (1620s). Related: Horrifically.