Related Clues:

• Negative influence
• Something harmful
• Toxic substance
• Murder method in Christie's 'A Pocket Full of Rye'
• Render impure
• Render unclean
• Foul the water, e.g.
• Opposite of "'tis"
• Reduce in status
• Arsenic, for one
• Weapon alternative in mysteries
• Whodunit staple
• Demoralize
• Depreciate or humiliate
• Make lower in prestige or esteem