- indispensable - not to be dispensed with; essential; "foods indispensable to good nutrition"
Antonym: dispensable
- essential, indispensable - absolutely necessary; vitally necessary; "essential tools and materials"; "funds essential to the completion of the project"; "an indispensable worker"
Antonyms: unnecessary, unneeded (indirect, via necessary)
- indispensable - unavoidable; "the routine but indispensable ceremonies of state"
Antonym: optional (indirect, via obligatory)