1.Definition: deprived of life; no longer living
"A lifeless body"
2.Definition: destitute or having been emptied of life or living beings
"After the dance the littered and lifeless ballroom echoed hollowly"
3.Definition: lacking animation or excitement or activity
"It was a lifeless party until she arrived"
4.Definition: not having the capacity to support life
"A lifeless planet"