A dishonourable action causes embarrassment and a loss of people's respect.

This was a dishonourable attempt to avoid responsibility. 这是逃避责任的不光彩的尝试。

They regard killing an unarmed man as dishonourable. 他们认为杀死一个手无寸铁的人是不光彩的。

A dishonourable person is not honest or fair, or does not deserve praise and respect.

I know him, and he is not a dishonourable man. 我了解他，他不是一个不诚实的人。