grim + reaper, first attested 1847. The word grim previously had a stronger meaning ("fierce, angry, sinister") and had more of an association with ghostliness (compare Old Englishgrima(“specter, apparition”), Englishgrim (n.)). The association between grim and death dates back to at least the late 16th century (the line "grim death, how foul and loathsome is thine image" appears in Shakespeare's The Taming of the Shrew around 1590). The reaper element comes from the personification of Death as a reaper (harvester) of souls in connection to to the popular depiction of Death wielding a scythe. The symbol of the scythe itself comes from a partially unintentional conflation of Cronus (the Titan associated with the harvest, said to have used his scythe to castrate his father Uranus) and Chronos (the personification of Father Time).