The word "bone-headed" means foolish or stupid. There are several synonyms that can be used to describe someone who is bone-headed. Some examples include dense, dim-witted, asinine, simple-minded, and idiotic. These words can be used to describe someone who lacks intelligence or common sense. Other possible synonyms for bone-headed are foolish, mindless, senseless, and daft. However, it's important to note that some of these words may carry a negative connotation and can be considered insulting. Therefore, it's important to use them carefully and only when appropriate.