It's not always polite or appropriate to call someone stupid. However, there are many different ways to describe someone who may not be the brightest bulb in the bunch. Some synonyms for stupid persons include unintelligent, foolish, dense, dim-witted, simple-minded, slow, clueless, and brainless. These words can be used in a variety of situations, whether you're trying to describe someone's actions, intelligence, or overall demeanor. It's important to choose your words carefully and use them respectfully, but having a wide range of synonyms for common words can help you better express yourself and avoid awkward or offensive situations.