形容詞 lifeless:

1. deprived of life; no longer living
   同義詞：exanimate
2. destitute or having been emptied of life or living beings
3. lacking animation or excitement or activity
   同義詞：dead
4. not having the capacity to support life

1. Lifeless, faultless.
   只有死人才不會犯錯誤。
2. It was a lifeless performance.
   那是一場死氣沉沉的演出。
3. The scientists guess that Venus is lifeless.
   科學家猜測在金星上沒有生命。

life.less

adj.（形容詞）
Having no life; inanimate.
無生命的；無知覺的
Having lost life; dead.See Synonyms at dead
死的；失去生命的參見 dead
Not inhabited by living beings; not capable of sustaining life.
無生命的；不能維持生命的
Lacking vitality or animation; dull:
沉悶的；乏味的：
例句：
a lifeless party.
索然無味的社交聚會

【引伸】
life.lessly
adv.（副詞）
life.lessness
n.（名詞）