翻訳　日本語　英語: 不可欠

1 BASIC, essential, necessary, necessity, requirement, requisite, staple.

2 CORE, Centre, PIN, center, essence, gist, heart, heart and soul, inwardness, kernel, marrow, meat, necessity, nitty-gritty, nub, pith, pivot, substance, sum.

3 certainty, foregone conclusion, inevitable, necessity, sure thing.

4 demand, essential, fire, firing, limitation, necessary, necessity, requirement, requisite.

5 demand, essential, indigence, necessary, necessity, need, pauperism, pauperization, penury, requirement, requisite, want.

6 demand, essential, necessary, necessity, prerequisite, requirement, requisite.

7 essential, essentiality, essentialness, necessary, necessity, requirement, requisite, requisiteness.

1 all important, all-important, cardinal, central, critical, crucial, essential, fundamental, imperative, indispensable, key, momentous, of the essence, pivotal, polar, primal, substantive, vital.

2 all important, all-important, compulsory, critical, crucial, essential, indispensable, mandatory, necessary, needed, needful, of the essence, required, requisite, vital.

3 all important, all-important, compulsory, crucial, essential, imperative, indispensable, mandatory, necessary, needed, needful, of the essence, required, requisite.

4 all important, all-important, crucial, essential, important, of the essence.

5 authoritative, cardinal, central, essential, foremost, frontmost, fundamental, important, key, leading, preeminent, primal, significant.

6 basal, basic, cardinal, central, elemental, elementary, essential, fundamental, introductory, key, pivotal, polar, primal, primary, rudimentary, standard, stock, underlying.

7 basal, essential, first, foremost, leading, preeminent, primary, world-class.

8 basic, cardinal, central, essential, fundamental, inner, internal, intimate, key, primal, profound.

9 basic, cardinal, central, essential, fundamental, key, primal, profound, rudimentary, underlying.

10 big, critical, crucial, essential, important, large, life-sustaining, material, meaningful, of import, prominent, significant, vital.

11 cardinal, central, essential, fundamental, important, independent, key, large, main, major, of import, primal, proto, significant, staple.

12 critical, crucial, dangerous, decisive, essential, grave, great, grievous, heavy, important, life-threatening, major, serious, severe, significant, weighty.

13 critical, crucial, decisive, essential, imperative, important, indispensable, vital.

14 critical, crucial, decisive, essential, important, of import, significant, vital.