What is the meaning of Stupid?

Without intelligence.

Lacking in intelligence.

Exhibiting the quality of having been done by someone lacking in intelligence.

Unpleasant; annoying to the speaker. This sense can be used alongside obscene words.

Usually replaces an obscene or profane word, and thus is audibly stressed as such.

To the point of stupor.

Characterized by or in a state of stupor; paralysed.

Lacking sensation; inanimate; destitute of consciousness; insensate.

Dulled in feeling or sensation; torpid.

Amazing.

Extremely.

A stupid person; a fool.

The condition or state of being stupid; stupidity, stupidness.

oafish

stupid (lacking in intelligence)

stupid

stupidly

Source: wiktionary.org