WordWeb Online

1. Of or related to or containing sulphur or derived from sulphur
   - sulfurous [N. Amer], sulphureous [Brit]
    
2. Harsh or corrosive in tone
   "a sulphurous denunciation"
   - acerb, acerbic, acid, acrid, bitter, blistering, caustic, sulfurous [N. Amer], virulent, vitriolic, sulphureous [Brit]
    
3. Characterized by oppressive heat and humidity
   "the sulphurous atmosphere preceding a thunderstorm"; "the summer was sulphurous and oppressive"
   - sultry, stifling, sulfurous [N. Amer], sulphureous [Brit]

See also: hot, sulphur [Brit, Cdn], unpleasant