Hindhead is a rare word that has very few synonyms. It refers to the part of a person's head that is situated behind the ears. Some of the words that are commonly used as synonyms for hindhead include nape, occiput, back of the head, and poll. While these words are somewhat similar in meaning, they don't have quite the same connotations as hindhead. This may be why people use the word hindhead to describe this part of the head in specific contexts, such as discussions about anatomy or medical diagnoses. However, in everyday conversation, it may be more common to use more general terms to refer to this area of the head.