When it comes to describing someone who is dull of mind, there are many synonyms you can use. Some of the most common include unintelligent, ignorant, dim-witted, dense, slow-witted, and unenlightened. Other options could include foolish, witless, blockheaded, and obtuse. You can also use more specific terms, such as lacking in common sense, or having a limited grasp of information. Regardless of the word you choose, it's important to remember that everyone has their own strengths and weaknesses, and intelligence can manifest in many different ways. So while someone may be dull of mind in one area, they may excel in other areas and display intelligence in different ways.