adjective
valuable, substantial
Synonyms: big, big-league, chief, considerable, conspicuous, critical, crucial, decisive, determining, earnest, essential, esteemed, exceptional, exigent, extensive, far-reaching, foremost, front-page, grave, great, heavy, imperative, importunate, influential, large, marked, material, mattering much, meaningful, momentous, necessary, of moment, of note, of substance, paramount, ponderous, pressing, primary, principal, relevant, salient, serious, signal, significant, something, standout, urgent, vital, weighty
Antonyms: inappreciable, insignificant, little, nonessential, small, trivial, unimportant, unsubstantial
adjective
eminent, influential, outstanding
Synonyms: aristocratic, big-time, distinctive, distinguished, effective, esteemed, extraordinary, famous, first-class, foremost, four-star, front-page, grand, heavy, high-level, high profile, high-ranking, high-up, honored, illustrious, imposing, incomparable, leading, majestic, major-league, noble, notable, noted, noteworthy, of note, page-one, potent, powerful, preeminent, prominent, remarkable, seminal, signal, solid, superior, talented, top-drawer, top-notch, upper-class, VIP, well-known
Antonyms: insignificant, powerless, unimportant, unknown, worthless