形容詞 harmless:

1. not causing or capable of causing harm
2. not injurious to physical or mental health
   同義詞：innocuous
3. not producing any toxic effects
4. unlikely to harm or disturb anyone
   同義詞：innocuous
5. not threatening to life or health; not malignant
   同義詞：nonmalignant

1. I made a harmless remark to some guy at the bar and he swung at me.
   在酒吧里我向某個(gè)家伙說(shuō)了句無(wú)惡意的話(huà)，他就向我打了一拳。
2. Causing no harm; harmless.
   無(wú)惡果的; 無(wú)害的
3. This snake is harmless.
   這條蛇是無(wú)毒的。
4. The bomb blast killed several harmless passers-by.
   炸彈爆炸使幾個(gè)無(wú)辜行人受傷。

harm.less

adj.（形容詞）
Incapable of causing harm.
不會(huì)造成傷害的
Free from loss or legal liability:
沒(méi)有受到損失或免于法律責(zé)任的：
例句：
Under the agreement, I would be held harmless if the other parties defaulted.
通過(guò)協(xié)定如果其他當(dāng)事人不出庭的話(huà)我將免于承擔(dān)法律責(zé)任

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