1. The quality or state of being fiendish; extreme wickedness, cruelty, or malice.
Usage: Plural form of fiendishness; Abstract noun expressing degree or instance of fiendish behavior

Examples

• The fiendishnesses displayed by the villain in the novel shocked readers.
• History records many fiendishnesses committed during times of war.
• The detective was appalled by the fiendishnesses evident in the crime scene.
• Such fiendishnesses are rarely seen in civilized society.
• The author explored various fiendishnesses of human nature in her work.