Related Clues:

• More than devilish
• The dark side
• Satanic
• Moral misdeed
• Trig function
• Trig ratio
• No-no
• What lurks in the hearts of men
• Satanicalness
• Very dark
• Like Lex Luthor
• First mistake
• Avarice, e.g.
• Major no-no
• Like some grins