Gasbag (noun)

1. A person who talks excessively and at length, especially about trivial or irrelevant matters.
2. A person who is full of hot air and talks too much and too loudly.

Origin:

First recorded use in 1877, origin is uncertain, but it is likely to come from the phrase "gas bag" which refers to a bag filled with hot air used in early airships.

Examples:

1. He's such a gasbag, he never stops talking.
2. She"s always been a bit of a gasbag, but I don"t mind because she"s so interesting.
3. He"s a gasbag and I can"t stand to be in the same room with him.
4. The meeting was dominated by a gasbag who wouldn't shut up.
5. He"s always been a gasbag, and he never stops talking, even when nobody"s listening.