devocalize or devocalise /dē-vōˈkə-līz/ or devoice /dē-voisˈ/

To make voiceless

• poisoned chalices
• poisoner
• poisoners
• poison-fang
• poison-fangs
• poison gas
• poison gases
• poison-gland
• poison-glands
• poisoning
• poison ivy
• poison-nut
• poison-nuts
• poison oak
• poison oaks
• poisonous
• poisonously
• poisonousness
• poisonousnesses
• poison pen
• poison pens
• poison pill
• poison pills
• poisons
• poison sumac