What is another word for "essential"?

Roget's Thesaurus (1911) lists these synonyms for "essential": able, absorbing, agalloch, ambrosial, and, aroma, aromatic, article, ask, attar, balm, balmy, bay, being, bergamot, blood, bodily, body, bottle, bouquet, calambac, calambour, call, cannot, case, charge, civet, claim, command, corporeal, corporeity, create, creature, crying, death, deficiency, demand, desiderate, desideratum, desire.