Empty-skulled is a derogatory term used to describe someone who is thought to be unintelligent or lacking in common sense. Fortunately, there are many synonyms that can be used to convey the same idea without using disparaging language. One such synonym is dull-witted, which implies a lack of mental acuity or quickness. Another synonym is simple-minded, suggesting a person who lacks complexity or depth of thought. Other alternatives include slow-witted, dense, and feeble-minded. Each of these synonyms can be used to describe someone who is not particularly bright or sharp without resorting to name-calling or belittlement.