Synonyms of indispensable

1 Syllable

keyer, key

2 Syllables

urgent, right-hand, basal, righthand, pointful, grass-roots, basic, grassroots, vital, rooter, needed, crucial, needful

3 Syllables

inherent, required, life-and-death, underlying, earthshaking, essential, cardinal, called-for, primary, integral, bottom-line, life-or-death, earth-shaking

4 Syllables

fundamental, earthshattering, requisite, bottomline, substrative, necessitous, mandatory, necessary, top-priority, all-important, name-of-the-game, coal-and-ice, earth-shattering

5 Syllables

compulsatory, imperative, axiological, applicative, unalienable, prerequisite