Bloggers dictionary:

blow-hard	(blo-'härd')
	–noun Slang. an exceptionally boastful and talkative person. [Origin: 1850–55, Americanism]
	See also: big head, big mouth, bullshitter, egotist, gasbag, know-it-all, neocon, swelled head, windbag
	Reference: Nitpicker