1. Exceedingly harmful
   - deadly, pernicious, pestilent 
2. Deadly or sinister
   - baleful

See also: maleficent, noxious

• tactless
• tactlessly
• tactlessness
• tactual
• tactual exploration
• tactual sensation
• tactually
• tad
• tadalafil
• Tadarida
• Tadarida brasiliensis
• Tadeus Reichstein
• Tadeusz Andrzej Bonawentura Kosciuszko
• Tadirida femorosacca
• Tadjik
• Tadorna
• tadpole
• tadpole shrimp
• tadpole-shaped
• Tadzhik
• Tadzhikistan
• Taegu
• taekwondo
• tael
• taenia