Airhead (noun)

A person who is considered to be empty-headed, silly or lacking intelligence.

Origin:

From the word "air" meaning "relating to air" and "head" meaning "the uppermost or forwardmost part of an object" or "a person"s mind or intellect", it is a term used in informal language.

Examples:

1. She was called an airhead for her inability to understand the situation.
2. He was being called an airhead for his lack of common sense.
3. Her friends thought she was an airhead for not noticing the obvious.
4. He was called an airhead for his lack of interest in serious matters.
5. She was considered an airhead by her colleagues because of her constant chatter.