The word bloviate is, according to Webster's internet dictionary, "an intransitive verb which means to speak or write at length in a pompous or boastful manner".  Bloviate is derived from the word blow (with a mock), with a faux Latin suffix -viate.  The noun form of the word is bloviation.

In 1967 Webster's Seventh New Collegiate Dictionary added bloviate to their edition defining it as "orating verbosely and windily", but then dropped it from their next edition and have added it back now as it shows up in my tenth edition.   The word is most widely used in the United States and does not appear in any of the British English dictionaries including the Oxford English Dictionary or the most recent New Oxford Dictionary of English.  Oxford, Macquarie, Penguin, Collins and Chambers editors have ignored the word completely.

One of my sources indicates that bloviate is mid-19th century American slang which "cleverly melds inklings of the blowhard with hints of blowing off steam, then subverts itself via self-mockery in its faux Latinate suffix".

The most famous person linked with the word bloviate is U.S. President Warren G. Harding who not only was described as a bloviator, but also used the word bloviate very often.  He was the epitome of someone who orates verbosely and windily.  When researching bloviate, President Harding's name came up several times, mostly saying the same thing about him though.  Harding did not invent the word, it is actually much older.  It had recently turned up in the middle of the last century and was found by Fred Shapiro of the Yale Law School.  For example, he found it in the Debates and Proceedings of the Convention for the Revision of the Constitution of the State of Ohio in 1851: "The bloviators attempt to disturb the proceedings of this Convention".  This example among other examples suggests it was a local word originating in Ohio, which was Harding's home state.  It is thought that bloviate fits in with the U.S. fashion of the early 19th century along with expansive mock Latinate words such as sockdolager, hornswoggle, and absquatulate.  There is a gap between here and the middle of the 20th century with the word bloviate.  It was only used again in the 1960s and even then was only linked to the President Warren G. Harding.  The word was only cited again in the 1990s and has become a favorite in the "weird words" circuit.

Here are a few examples of how the word bloviate has been used in more recent journalism.

"Anyone who has ever spent an idle morning watching the Washington talk shows has probably wondered: how did these people become entitled to earn six-figure salaries bloviating about the week's headlines?
--Robert Worth, New York Times, June 3, 2001

"After five years as president and thirty years as a political figure, this colossal oaf is still unable to discipline his urge to... bloviate. --R. Emmett Tyrrell, Jr., American Spectator, December 19, 1997


Sources:
Australian, The; 12/07/2002 By Murray Waldren
Insight on the News; 8/19/2002, Vol. 18 Issue 30, p4, 1/2p By Stephen Goode
Dictionary.com
www.worldwidewords.org