1. important
1. all-important, all important, crucial, essential, of the essence, alpha, arch, big, burning, cardinal, central, fundamental, key, primal, chief, main, primary, principal, consequential, eventful, Copernican, distinguished, eminent, great, grave, grievous, heavy, weighty, historic, in-chief, measurable, most-valuable, serious, strategic, useful, valuable, of value, beta, essential, significant, important, valuable