If you do something laughingly, you are laughing while you are doing it.

He laughingly pointed out our mistakes. 他面带笑容地指出了我们的错误。

If you say something is laughingly described in a particular way, you think this thing is so bad that it does not deserve the description.

It is only one of the absurd rules in the system of law laughingly known as British justice. 这只是被冠冕堂皇地称作英国司法的法律体系中荒唐的法律规定之一。