all–important

impossible to do without that all-important item for a successful birthday party: a fancily decorated cake with candles Synonyms all-important, critical, imperative, indispensable, integral, must-have, necessary, necessitous, needed, needful, required, requisite, vitalRelated Words prerequisite; compulsory, mandatory, nonelective, obligatory; consequential, crucial, important, major, material, meaningful, momentous, significant, substantial, weighty; basic, central, fundamental, key, organic; insistent, persistent, pressing, urgentNear Antonyms undesired, unwanted; inconsequential, insignificant, unimportant; excess, external, extra, extraneous, superfluous, surplusAntonyms dispensable, inessential, needless, nonessential, unessential, unnecessary, unneeded