请你提供网络词典名称。

I don't know as he is stupid.这句话怎么理解？

as he is stupid 是什么从句？

What you can get  is that the mentioned-above is a wrong sentence which is seriously against English grammatical rules that must be obeyed while an English sentence is being created. Please offer the provenance of the above sentence so that you can get a better answer to the question which was presented by you. 

语法有点……

as引导定语从句，状语从句。你句子出处……