Heavyweight

Noun

 * 1) A very large, heavy or impressive person.
 * 2) The professional boxing weight division for boxers weighing more than 190 pounds; a boxer in that division.
 * 3) A similar division and contestant in other sports.

Adjective

 * 1) Of the heavyweight boxing (or similar) division.
 * 2) Being relatively heavy.
 * 3) Being a leader in one's field.

Thesaurus
Chinese boxer, Rasputin, Svengali, VIP, access, bad influence, bantamweight, big, big boy, big cheese, big wheel, big-league, big-name, big-time, big-timer, bigwig, bigwigged, black belt, blimp, boxer, brown belt, bruiser, catchweight, chief, consequential, considerable, court, double-barreled, earthshaking, eminence grise, fat, fat cat, fatty, featherweight, fighter, fisticuffer, five-percenter, flyweight, friend at court, good influence, grand, gray eminence, great, heavy, hefty, hidden hand, high-powered, hippo, important, influence, influence peddler, influencer, ingroup, karate expert, key, kingmaker, leaden, leader, light heavyweight, lightweight, lion, lobby, lobbyist, lords of creation, lump, major, man of influence, manipulator, massive, massy, material, middleweight, momentous, name, open sesame, overweight, palooka, ponderous, potbelly, powers that be, pressure group, prizefighter, pug, pugilist, roly-poly, savate expert, self-important, significant, sinister influence, sparrer, special interests, special-interest group, substantial, superior, swagbelly, the Establishment, tub, tub of lard, tun, very important person, weighty, welterweight, wheeler-dealer, wire-puller, world-shaking