patricide (n.)

1. "person who kills his father" (1590s), 2. "act of killing one's father" (1620s), from Middle French patricide in both senses, presumed to be from 1. Latin *patricida "murderer of a father," 2. Latin *patricidium "killing of a father," from pater "father" + 1. cida "killer," 2. cidium "killing" (both from PIE root *kae-id- "to strike"). The usual classical Latin form was parricida/parricidium.