crucialnecessarykeyvitalindispensableneededrequiredcalled forrequisiteimportantall-importantvitally importantof the utmost importanceof great consequenceof the essencecriticallife-and-deathimperativemandatorycompulsoryobligatorycompellingurgentpressingburningacuteparamountpreeminenthigh-prioritysignificantconsequential
2
Medicine
(of a disease) with no known external stimulus or cause; idiopathic.
essential hypertension
名词
1
a thing that is absolutely necessary.
we had only the bare essentials in the way of gear
同义词：
necessitynecessary/essential itemprerequisiterequisiterequirementneedconditionpreconditionspecificationstipulationqualificationdesideratumsine qua noninformal：must
