Irish pennant

(slang) A brick or bricks thrown during a fight.

(Ireland) An insignificant person.

Irish confetti is a darkly humorous American and British slang phrase for bricks — specifically bricks thrown as weapons during a fight or riot. The term reflects an old ethnic stereotype associating Irish immigrants with street brawls and construction work. Its origins lie in the kind of derogatory ethnic humour that was common in the 19th and early 20th centuries. Today the phrase is considered offensive and is rarely used without awareness of its prejudiced roots. It's the kind of expression that turns up in historical texts or discussions of slang rather than current casual use.

(historical, Ireland, UK) A halfpenny; a former British and Irish coin.