Is "Stupid" a bad word? If someone said to you, " you are stupid", how would you feel?

Well, stupidity is simply another word for ignorance, and in a much broader way, it could be as awful as being ignorant about one's ignorance itself. The truth is, virtually everyone is stupid. But that's okay.

Why Are People So Stupid?

It doesn't really make any sense to rashly sum up the entire complexity of human behavior in a single word as 'stupidity'. To the extent that stupidity implies low intelligence, it is a phrase which could accurately describe only an aspect of some people, and should not to be taken extremely literally or as a label.

More here: Is Supidity a Bad Word?