weighty

big, consequential, eventful, important, major, material, meaningful, momentous, portentous, significant, solid, substantial

decisive, fatal, fateful, strategic

earnest, grave, heavy, serious, sincere

distinctive, exceptional, impressive, outstanding, prominent, remarkable

valuable, worthwhile, worthy

distinguished, eminent, great, illustrious, noble, notable, noteworthy, outstanding, preeminent, prestigious

famous, notorious, renowned

all-important, central, critical, crucial, essential, key, pivotal, seminal, vital

burdensome, leaden, lumpish

bulky, elephantine, massy, outsize (also outsized), voluminous

overweight, top-heavy

solid, substantial

ultraheavy

harsh, stern, strict

businesslike, professional

dignified, distinguished, elevated, serious-minded

gloomy, grim

cogent, controlling, dominating, masterful

dominant, predominant, regnant, sovereign (also sovran), supreme

eminent, important, momentous