I wish more people knew this word, in part because then it could be used more effectively to admonish people (and especially lawyers and politicians who go on for paragraphs while saying nothing). According to dictionary.com, it means "To discourse at length in a pompous or boastful manner." And to my knowledge, there are no good and more familiar one-word synonyms.

UPDATE: Some people suggest "pontificate," which also refers to pompous talk; but I think "bloviating" suggests something more verbose than merely pontificating.