IPA: /ˈboʊstər/
KK: /ˈboʊstər/
A person who talks too proudly about their achievements or abilities.
He is such a boaster, always bragging about his accomplishments.
Boaster → The word is formed from "boast" (from Old French *boaster*, meaning to brag or speak with pride) and the suffix "-er" (meaning a person who). A boaster is a person who brags or speaks with pride about their achievements or qualities.
Think of someone who 'brags' ('boast') about their accomplishments — the '-er' indicates that this person is the one doing the boasting.