1.
If a person or animal is lifeless, they are dead, or are so still that they appear to be dead.
Their cold-blooded killers had then dragged their lifeless bodies upstairs to the bathroom...
ADJ
2.
If you describe an object or a machine as lifeless, you mean that they are not living things, even though they may resemble living things.
It was made of plaster, hard and white and lifeless, bearing no resemblance to human flesh.
ADJ
3.
A lifeless place or area does not have anything living or growing there at all.
Dry stone walls may appear stark and lifeless, but they provide a valuable habitat for plants and animals.
ADJ
4.
If you describe a person, or something such as an artistic performance or a town as lifeless, you mean they lack any lively or exciting qualities.
...a lifeless portrait of an elderly woman.
ADJ [disapproval]