It isn't unlawful, but it's morally wrong.

这事不算违法, 但在德上是错。

I’m morally under obligation to do the best I can by her.

我在义上有责任尽量善待她。

"What you did wasn't actually against the law, but it was morally wrong."

"你所做事并未真正触犯法律,但在义上是错。"

I felt morally obliged to do the best I could for her.

义上我感觉必须尽我所能为她效劳。

The attempt is morally bound to fail.

这一企图肯定会失败。

I am morally certain that he is incapable of deliberately harming anyone.

我确实认为他不会蓄意伤人。

Can her actions be morally justified?

她行为合乎德原则吗？

He's morally obscene.

他是一个德败坏家伙。