ETYM Cf. French essentiel. Related to Essence.
1. Absolutely necessary; vitally necessary; SYN. indispensable.
2. Absolutely required and not to be used up or sacrificed.
3. Basic and fundamental.
4. Being or relating to or containing the essence of a plant etc.
all important · all-important · basal · biogenic · constituent · constitutional · constitutive · crucial · important · indispensable · intrinsic · intrinsical · life-sustaining · matter · must · necessary · no-frills · of import · of the essence · organic · primary · staple · substance · substantial · substantive · unexpendable · virtual · vital
1. Something basic
2. Something necessary, indispensable, or unavoidable