1. Exceedingly harmful
   - baneful, deadly, pernicious 
2. Likely to spread and cause an epidemic disease
   - pestilential, pestiferous, plaguey

See also: epidemic, noxious, pestilence

• browned
• browned off
• brownfield
• Brownian motion
• Brownian movement
• brownie
• brownie mix
• Brownie point
• browning
• Browning automatic rifle
• Browning machine gun
• brownish
• brownish yellow
• brownish-black
• brownish-gray
• brownish-green
• brownish-grey
• brownish-orange
• brownish-purple
• brownish-red
• brownish-speckled
• brownish-striped
• brownness
• brownout
• Brownshirt