of much or great significance or consequence

an important event in world history.

mattering much (usually fol. by to )

details important to a fair decision.

entitled to more than ordinary consideration or notice

an important exception.

prominent or large

He played an important part in national politics.

of considerable influence or authority, as a person or position

an important scientist.

having social position or distinction, as a person or family

important guests.

pompous; pretentious

When speaking, he assumes an important attitude that offends his audience.

Obsolete . importunate.

adjective

inappreciable , insignificant , little , nonessential , small , trivial , unimportant , unsubstantial , powerless , unknown , worthless

adjective

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 , aristocratic , big-time , distinctive , distinguished , effective , extraordinary , famous , first-class * , four-star , grand , heavy * , high-level , high profile , high-ranking , high-up , honored , illustrious , imposing , incomparable , leading , majestic , major-league , noble , notable , noted , noteworthy , page-one , potent , powerful , preeminent , prominent , remarkable , seminal , solid , superior , talented , top-drawer , top-notch * , upper-class , vip * , well-known , consequential , historic , monumental , substantial , earthshaking , eminent , epochal , major , pivotal , pompous , strategic , striking , valuable