A lively, energetic, or highly capable boy or young man. Hyphenated if used as a modifier before a noun. Primarily heard in Ireland. It's hard to imagine just by looking at him that this tousle-haired broth of a boy could be one of the greatest scientific minds in the country. The rugby star uses his cheery, broth-of-a-boy demeanour to hide the ruthlessness of his skills on the pitch.