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

See also: epidemic, noxious, pestilence

• clubber
• clubbing
• clubbish
• clubby
• clubfoot
• clubfooted
• clubhead
• clubhouse
• clubland
• clubmoss family
• clubroom
• clubroot fungus
• cluck
• clucking
• clue
• clue in
• clued-up
• clueless
• clumber
• clumber spaniel
• clump
• clumping
• clumpy
• clumsily
• clumsiness