beat one's chest

English

Etymology

The bragging sense may have come from, and certainly connotatively evokes, the theme of gorillas beating their chests in displays of dominance, aggression, defense, or otherwise.

Verb

beat one's chest (third-person singular simple present beats one's chest, present participle beating one's chest, simple past beat one's chest, past participle beaten one's chest or (colloquial) beat one's chest)

2. To brag ostentatiously.

   beating his chest about his accomplishments

4. Synonym of beat one's breast (“lament”)