essential

essential

名词 essential:

anything indispensable

同义词：necessity, requirement, requisite, necessary

形容词 essential:

absolutely necessary; vitally necessary

同义词：indispensable

basic and fundamental

of the greatest importance

同义词：all-important, all important, crucial, of the essence

being or relating to or containing the essence of a plant etc

defining rights and duties as opposed to giving the rules by which rights and duties are established

同义词：substantive

absolutely required and not to be used up or sacrificed