Air-headed refers to someone who is foolish or not very intelligent. There are many different words that can be used as synonyms for air-headed depending on the context of the sentence. Some examples of synonyms might include daft, ditsy, or scatterbrained. Other possible synonyms may include frivolous, flippant, or flighty. Still, others may use terms such as mindless, vacuous, or clueless to describe someone who is air-headed. Whatever the word choice may be, each synonym emphasizes the same idea of someone who seems to be lacking in common sense or intelligence.