I came across this word in the letters to the editor in the Providence Journal this morning and had never seen it before. As a word hound, I immediately ran to my cheap-ass American Heritage Collegiate dictionary and it was nowhere to be found.
Since the OED is in boxes in the attic, I jumped online (thank God for the internet) and found that it was slang. Hence it's exclusion from the AH 2nd College Edition. (Will somebody PLEASE get me the American Heritage 4th edition for Christmas?!?!)
The writer of the letter in the Projo was asking someone critical of the Bush administration to stop bloviating if they don't know what they are talking about. The writer was from Texas. How they ended up published in a Rhode Island newspaper, I don't know. Maybe it was because they used a fancy word that would send us bloviating New Englanders to the dictionary.
Laconic I ain't.