Someone who's lifeless has died. Your lifeless house plant probably got that way because you forgot to water it.

You can use the adjective lifeless to describe once-living things, like people, animals, and plants, and you can also use it for objects that appear inert: "The creepy thing about that painting is the clown's lifeless eyes." Things that are duller or droopier than they should be are also lifeless, like your lifeless hair or a writer's lifeless prose. Less common is using lifeless to mean "with no living things," like the lifeless planet Venus.

Definitions of lifeless

adj deprived of life; no longer living

“a lifeless body”
no longer having or seeming to have or expecting to have life

adj destitute or having been emptied of life or living beings

“after the dance the littered and lifeless ballroom echoed hollowly”
holding or containing nothing

adj lacking animation or excitement or activity

“it was a lifeless party until she arrived”
not animated or enlivened; dull

adj not having the capacity to support life

“a lifeless planet”
not showing characteristics of life especially the capacity to sustain life; no longer exerting force or having energy or heat

Sign up, it's free!

Whether you're a student, an educator, or a lifelong learner, can put you on the path to systematic vocabulary improvement.