Thick-pated is a derogatory term used to describe someone who is slow, dull-witted, or foolish. There are plenty of synonyms that can be used instead of thick-pated to avoid insulting someone's intelligence. Some alternatives include dim-witted, dense, obtuse, and unintelligent. Other synonyms that can be used are brainless, clueless, doltish, and ignorant. These words can describe someone who lacks the ability to understand or comprehend something easily. It's important to be careful when choosing words to describe someone else, especially when it comes to discussing their intelligence. Using words that aren't insulting and derogatory is always a smart choice.