1. in the sense of crucial
- necessary
- crucial
- vital
- key
- needed
- indispensable
- called for
- required
- important
- requisite
- vitally important
- all-important
- of great consequence
- of the utmost importance
- critical
- of the essence
- imperative
- life-and-death
- compulsory
- mandatory
- compelling
- obligatory
- pressing
- urgent
- acute
- burning
- pre-eminent
- paramount
- significant
- high-priority
- consequential
2. in the sense of basic
- inherent
- basic
- quintessential
- fundamental
- underlying
- intrinsic
- innate
- characteristic
- primary
- rudimentary
- cardinal
- principal
- elementary
- chief
- central
- elemental
- critical
- pivotal
- focal
- key
- staple
- salient
- necessary
- vital
- foundational
- indispensable
- ingrained
3. in the sense of necessity
- necessary/essential item
- necessity
- requisite
- prerequisite
- need
- requirement
- precondition
- condition
- stipulation
- specification
- desideratum
- qualification
- must
- sine qua non
4. in the sense of fundamentals
Example Sentences of Essential
1. Water is essential for life.
2. Safety is essential at work.
3. Vitamins are essential for health.
4. It's essential to stay focused.