Here are some of the most common ways to say stupid in Spanish:
1. **Tonto/a** – This is the most basic way to say stupid in Spanish. It can be used in a variety of contexts, but is generally considered to be derogatory.
2. **Estúpido/a** – This is another common way to say stupid, but is more intense than tonto/a.
3. **Bobo/a** – This word directly translates into “fool.” This is one of the less offensive ways to call someone stupid in Spanish, and is often used in an affectionate way.
4. **Idiota** – This word can be used as either an adjective or as a noun—in either case, the masculine form is “idiota,” and the feminine form is “idiota” as well.