of prime importance; chief; principal

of cardinal significance.

of the color cardinal.

Roman Catholic Church . a high ecclesiastic appointed by the pope to the College of Cardinals and ranking above every other ecclesiastic but the pope.

Also called cardinal grosbeak. a crested grosbeak, Cardinalis cardinalis, of North America, the male of which is bright red.

any of various similar birds.

a deep, rich red color.

a woman's short cloak with a hood, originally made of scarlet cloth and popularly worn in the 18th century.

cardinal number.

adjective

inessential , insignificant , minor , negligible , secondary , unimportant

adjective

basal , basic , central , chief , constitutive , essential , first , foremost , fundamental , greatest , highest , indispensable , leading , main , overriding , overruling , paramount , pivotal , preeminent , primary , prime , principal , ruling , vital , capital , key , major , number one , premier , top , cleric , cloak , head , important , number , preminent , red , superior , underlying , uppermost