The phrase "to dumb down" means to make something or someone less intelligent, complex, or challenging. It is often used in a negative way when referring to how information or content may be simplified or watered-down for mass consumption, resulting in the loss of important details or nuance. The term can also refer to an attempt to appeal to a broader audience by making something more accessible and easier to understand, regardless of whether it is perceived as being "dumbed down" or not.