In Spanish, the word for ‘stupid’ is estúpido when referring to a masculine noun and estúpida for a feminine noun. This term is used in a similar context as in English, to describe someone who is making a foolish mistake or lacks intelligence.
For example, you might say, "Él es muy estúpido" to mean "He is very stupid." If you were talking about a female, you would say, "Ella es muy estúpida." It’s important to use this word with caution, as it can be considered offensive in certain contexts.