blowhard (n.)youdaoicibaDictYouDict[blowhard 词源字典]
also blow-hard, 1840, a sailor's word (from 1790 as a nickname for a sailor), perhaps not originally primarily meaning "braggart;" from blow (v.1) + hard (adv.). An adjective sense of "boastful" appeared c. 1855, and may be a separate formation leading to a modified noun use.[blowhard etymology, blowhard origin, 英语词源]