WordWeb Online

1. Deprived of life; no longer living
   "a lifeless body";
   - exanimate
    
2. Destitute or having been emptied of life or living beings
   "after the dance the littered and lifeless ballroom echoed hollowly"
    
3. Lacking animation, excitement or activity
   "it was a lifeless party until she arrived"
    
4. Not having the capacity to support life
   "a lifeless planet"

See also: dead, empty, unanimated

Encyclopedia: Lifeless