Definition

Lacking intelligence, common sense, or mental sharpness; displaying foolish behavior or poor reasoning. Stronger and more dismissive than 'dumb.'

Example Usage

I can't believe I made such a stupid mistake on the exam.

Origin

From Latin 'stupidus' (amazed, senseless), derived from 'stupere' (to be stunned or astonished).

Fun Fact

Psychologically, calling oneself or others 'stupid' is often a harsh form of self-criticism that doesn't actually improve decision-making.

Source: Definition backfill (hailey)