heavyweight /ˈhɛ.vi.weɪt/adjective 4noun 3forms 1 adjective4 •Being relatively heavy. •Being a leader in one's field. •Important or impressive.The Olympics, the weather and a comparative lack of heavyweight clashes so far this season have been cited as reasons for the drop in viewers. — 2016 •Of the heavyweight boxing (or similar) division. noun3 •The professional boxing weight class for boxers weighing more than 190 pounds; a boxer in that division. •A very large, heavy, or impressive person.Allen Gregory DeLongpre: Who's he? Patrick: He's only the most popular kid in school. Allen Gregory: Ah, the two heavyweights finally meet. Sure you're tired of all the buzz. Allen Gregory DeLongpre. — 2011 •A similar division and contestant in other sports. formsheavyweights