Jolthead is a term that is not frequently used in everyday language and is often seen as an insult or derogatory term for a foolish or incompetent person. However, there are several synonyms that share a similar meaning, such as blockhead, dunce, numbskull, simpleton, moron, and dimwit. These words all describe someone who is lacking in intelligence or common sense. Depending on the context, some other alternatives may include ignoramus, nitwit, dolt, or imbecile. It is important to remember to use these words with caution as they can be offensive and hurtful if used inappropriately.