1. the quality or state of being deadly; the capacity or likelihood to cause death or serious harm

Examples

• The deadliness of the virus became apparent as cases increased worldwide.
• Doctors warned about the deadliness of untreated infections.
• The deadliness of the storm forced authorities to issue evacuation orders.
• Scientists studied the deadliness of various toxins in the laboratory.
• The deadliness of the disease made prevention efforts a top priority.
• He spoke about the deadliness of distracted driving to the high school assembly.