To bloviate is to talk, but not just to chat. To bloviate means to go on and on and on and on, usually in a pompous way.
Can you hear the blow in the word bloviate? That's a clue that someone bloviating is blowing some serious hot air. When someone bloviates, he is speaking in an empty, pretentious, full-of-himself manner. This word is often associated with politicians, who probably invented bloviating. When someone is talking a lot and saying a little, they're bloviating.