blowhard:
(plural: ‘blowhards‘; pronunciation: ‘blow…hard’)
a blowhard (L) bragging and boring a listener (R)
a noisy person with a high, perhaps too high, opinion of himself, i.e. thinks and talks too much about his greatness — talkative and boastful;
a person who brags about him/herself;
a bragger; a blower (previous entry);
a boaster; a braggart,
a blowhard (L) showing off his sergeant chevron to his junior (R)
In our office, Mr. Keats calls Mr. Pete a blowhard, and Mr. Pete calls Ms. Jane a blowhard, and we the rest of the staff know that those three are blowhards.
A person who has worked hard to reach the top position may brag and we never bother to call him/her a blowhard, but when the one who has no talent of whatsoever brags, we definitely feel happy to call him/her a braggart, boaster and blowhard!
