indispensable

(noun, adjective)

adjective

1. not to be dispensed with; essential

- foods indispensable to good nutrition

Similar word(s): critical, vital, necessary

2. absolutely necessary; vitally necessary

- an indispensable worker

Similar word(s): necessary, essential

3. unavoidable

- the routine but indispensable ceremonies of state

Similar word(s): obligatory

Sentences with indispensable as an adjective:

- The law was moral and indispensable. -Bp. Burnet

- An indispensable component of a heart-healthy diet.

noun

1. A thing that is not dispensable; a necessity. [from 17th c.]

2. (in the plural, colloquial, dated) Trousers. [from 19th c.]