Adjective:

1. beyond doubt or reproach;

   "an unimpeachable source"
   

2. free of guilt; not subject to blame;

   "has lived a blameless life"
   "of irreproachable character"
   "an unimpeachable reputation"
   

3. completely acceptable; not open to exception or reproach;

   "two unexceptionable witnesses"
   "a judge's ethics should be unexceptionable"
   

1.无可怀疑的；完全可靠的
If you describe someone asunimpeachable, you mean that they are completely honest and reliable.

e.g. He said all five were men ofunimpeachable character.
他说这五个都是品格完美无缺的人。
e.g. ...anunimpeachable source.
可靠的来源

1. 无过失的：unimaginative 缺乏想象力的 |unimpeachable 无过失的 | unimpeachably 无可指责地

2. 无可指摘的,无可置疑的：indefatigable不知疲倦的 |unimpeachable无可指摘的,无可置疑的 | irreproachable不可指责的,无过失的

3. 无懈可击的/无可指责的/无过失的：unimpaired /健全/ |unimpeachable /无懈可击的/无可指责的/无过失的/ | unimpeachably /无可指责地/

4. 完美无瑕：regression 退步 |unimpeachable 完美无瑕 | parable 寓言

evidence from an unimpeachable source

来源可靠的证据

He said all five were men of unimpeachable character.

他说这五个都是品格完美无缺的人。

...an unimpeachable source.

可靠的来源

This is market rule, unimpeachable.

这是市场规律, 无可指责.

Your testimony on this matter is hardly unimpeachable.

在这个问题上你的辩驳很难说是无懈可击的.

And that she had been told by the most unimpeachable source: his mother.

告诉她这一情况的,原来就是他的母亲.

It is the revenge that nature takes on persons of unimpeachable character.

这是自然对人品无瑕的人的报复.

Their actions are selfless and unimpeachable.

他们的行动是无私的,是无可指责的.

All round the table, the gentlemen looked unimpeachable in the extreme.

这些绅士们围着桌子坐着, 样子都极端地无可非议.

I have it on unimpeachable authority.

我从绝对可靠的权威处获悉该消息.

Willoughby Pattern is a man of unimpeachable honour.

威洛比·帕忒恩是个无可指责的高尚的人.

He said all five were men of unimpeachable character.

他说这五个都是品格完美无缺的人。

evidence from an unimpeachable source

来源可靠的证据