important

1 having great meaning or lasting effect the discovery of penicillin was a very important event in the history of medicine Synonyms big, consequential, earthshaking, earth-shattering, eventful, historic, major, material, meaningful, momentous, monumental, much, significant, substantial, tectonic, weighty Related Words 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 Near Antonyms paltry, petty, worthless; anonymous, nameless, obscure, uncelebrated, unknown Antonyms inconsequential, inconsiderable, insignificant, little, minor, negligible, slight, small, trifling, trivial, unimportant

2 having great power or influence Rachel Carson was an important figure in the environmental movement Synonyms heavy, heavy-duty, influential, mighty, potent, powerful, puissant, significant, strong Related Words high-level, senior, top; able, capable, competent, effective, efficient; authoritarian, autocratic (also autocratical), despotic, dictatorial, magisterial, tyrannical (also tyrannic); celebrated, distinguished, dominant, eminent, famed, famous, great, illustrious, noble, notable, noteworthy, notorious, outstanding, preeminent, prestigious, prominent, renowned; dynamic, energetic, forceful, high-powered, robust, vigorous Near Antonyms feeble, flimsy, frail, infirm; anonymous, nameless, obscure, uncelebrated, unknown; incapable, incompetent, ineffective, inept, inexpert, unfit, unqualified, unskilled, unskillful Antonyms helpless, impotent, insignificant, little, powerless, unimportant, weak

3 having a feeling of superiority that shows itself in an overbearing attitude an important businessman who always expects special treatment wherever he goes Synonyms assumptive, bumptious, cavalier, chesty, haughty, highfalutin (also hifalutin), high-and-mighty, high-handed, high-hat, huffish, huffy, imperious, arrogant, lofty, lordly, masterful, overweening, peremptory, pompous, presuming, presumptuous, pretentious, self-asserting, self-assertive, sniffy, stiff-necked, supercilious, superior, toplofty (also toploftical), uppish, uppityRelated Words authoritarian, bossy, dominant, dominating, domineering, magisterial, pontifical, pontificating; condescending, disdainful, patronizing; impertinent, impudent, saucy; snobbish, snobby, snooty; blusterous, blustery, boastful, bombastic, braggart, bragging, braggy, cocky, swaggering, vain, vainglorious; complacent, conceited, egocentric, egoistic (also egoistical), egotistic (or egotistical), hubristic, narcissistic, orgulous, prideful, proud, self-affected, self-applauding, self-centered, self-complacent, self-conceited, self-pleased, self-satisfied, smug, stuck-up; self-flattering, self-loving, self-promoting; brash, forward, uninhibited, unreserved; extroverted (also extraverted), immodestNear Antonyms bashful, cowering, cringing, demure, diffident, introverted, mousy (or mousey), overmodest, self-critical, self-doubting, sheepish, shrinking, shy, subdued, timid; acquiescent, compliant, deferential, meek, passive, submissive, unaggressive, unassertive, unassuming, unobtrusive, yielding; quiet, reserved, retiringAntonyms humble, lowly, modest, unarrogant, unpretentious

4 having too high an opinion of oneself oh, you're so important—you think the world revolves around you Synonyms assured, biggety (or biggity) [Southern & Midland], bigheaded, complacent, consequential, egoistic (also egoistical), egotistic (or egotistical), conceited, overweening, pompous, prideful, proud, self-conceited, self-important, self-opinionated, self-satisfied, smug, stuck-up, swellheaded, vain, vaingloriousRelated Words blusterous, blustery, boastful, bombastic, braggart, bragging, braggy, cocky, swaggering; arrogant, assumptive, bumptious, cavalier, chesty, disdainful, fastuous, haughty, high-and-mighty, high-hat, huffy, lofty, lordly, masterful, peremptory, pontifical, self-asserting, self-assertive, snobbish, snobby, snooty, supercilious, superior, toplofty (also toploftical), uppish, uppity; domineering, high-handed, imperious; highfalutin (also hifalutin), holier-than-thou, pretentious; overconfident, presuming, presumptuous; confident, self-assured, self-confident; self-adulatory, self-congratulatory, self-contented, self-gratulatory; self-applauding, self-dramatizing, self-glorifying, self-promoting; self-affected, self-centered, self-engrossed, selfish; condescending, patronizingNear Antonyms diffident, self-critical, self-distrustful, self-doubting, self-reproachful, self-reproving; meek, timid, unassertive; down-to-earth, unarrogant, unassuming, unpretentious; bashful, demure, introverted, mousy (or mousey), overmodest, retiring, sheepish, shrinking, shyAntonyms egoless, humble, modest, uncomplacent