Informal verb meaning ‘to talk at length, esp. idly or pompously’
Definitions
To talk idly, aimlessly, or pompously and at great length; to gossip. They sat on the porch gasbagging about old times until midnight.
Attributive use before a noun; treated as adjective
Definitions
Relating to or characteristic of someone who talks too much or of a container filled with gas (used attributively). The senator’s gasbag speech bored everyone in the chamber.