Blockheaded is a term used to describe someone who is not very intelligent or quick-witted. It can be used to describe someone who is slow to understand, or someone who is not very bright. The term can be broken down into three synonyms: DOLTISH (7 letters), THICK (5 letters), and DENSE (5 letters). DOLTISH means foolish or stupid, THICK implies a lack of intelligence, and DENSE suggests a person who is slow to understand. All three words can be used to describe someone who is blockheaded.