1. A very boastful and talkative person; a braggart

2. A self-important egomaniac who likes to toot his own horn, like those assholes who put bumper stickers on their cars that say "PROUD PARENTS OF AN HONOR STUDENT AT (blah blah blah) HIGH SCHOOL"

Someone who boasts excessively and exaggeratively about his or her imagined talents or abilities. Also characteristic of someone who thinks they know something that others do not. Blow-hards are akin to name-droppers.

Someone who talks a lot.

Someone who likes to shamelessly talk out of their ass.

A person that is known to rant and rave about things. Their opinions are usually ignorant and lack evidence. The term comes from the literal meaning of "blowing hard". If you blow hard enough people pretty much have to listen.

an opinionated person who talks loud and way too long on the same subject, often sensationalizing the subject matter

Someone who speaks loud and long, offering an opinion YOU disagree with.