lifeblood β the blood, considered as essential to maintain life: to spill one's lifeblood in war.
essence β The intrinsic nature or indispensable quality of something, esp. something abstract, that determines its character.
quintessence β the pure and concentrated essence of a substance.
sine qua non β an indispensable condition; requisite.
necessity β something necessary or indispensable: food, shelter, and other necessities of life.
basic β You use basic to describe things, activities, and principles that are very important or necessary, and on which others depend.
condition β If you talk about the condition of a person or thing, you are talking about the state that they are in, especially how good or bad their physical state is.
element β A part or aspect of something abstract, especially one that is essential or characteristic.
fundamental β serving as, or being an essential part of, a foundation or basis; basic; underlying: fundamental principles; the fundamental structure.
must β to be obliged; be compelled: Do I have to go? I must, I suppose.
precondition β something that must come before or is necessary to a subsequent result; condition: a precondition for a promotion.
prerequisite β required beforehand: a prerequisite fund of knowledge.
principle β an accepted or professed rule of action or conduct: a person of good moral principles.
requirement β that which is required; a thing demanded or obligatory: One of the requirements of the job is accuracy.
requisite β required or necessary for a particular purpose, position, etc.; indispensable: the requisite skills of an engineer.
groceries β Also called grocery store. a grocer's store.
guts β the alimentary canal, especially between the pylorus and the anus, or some portion of it. Compare foregut, midgut, hindgut.
heart β Anatomy. a hollow, pumplike organ of blood circulation, composed mainly of rhythmically contractile smooth muscle, located in the chest between the lungs and slightly to the left and consisting of four chambers: a right atrium that receives blood returning from the body via the superior and inferior vena cavae, a right ventricle that pumps the blood through the pulmonary artery to the lungs for oxygenation, a left atrium that receives the oxygenated blood via the pulmonary veins and passes it through the mitral valve, and a left ventricle that pumps the oxygenated blood, via the aorta, throughout the body.
nitty-gritty β the essential substance or details of a matter; basics; crux: Let's skip the chitchat and get down to the nitty-gritty.
rudiment β Usually, rudiments. the elements or first principles of a subject: the rudiments of grammar. a mere beginning, first slight appearance, or undeveloped or imperfect form of something: the rudiments of a plan.
stuff β the material of which anything is made: a hard, crystalline stuff.
substance β that of which a thing consists; physical matter or material: form and substance.
bottom line β The bottom line in a decision or situation is the most important factor that you have to consider.
brass tacks β basic realities; hard facts (esp in the phrase get down to brass tacks)
name of the game β the essential element, consideration, or ultimate purpose; key: Profit is the name of the game in business.
nuts and bolts β the essential or basic aspects: to learn the nuts and bolts of a new job.
part and parcel β a portion or division of a whole that is separate or distinct; piece, fragment, fraction, or section; constituent: the rear part of the house; to glue the two parts together.
necessary β being essential, indispensable, or requisite: a necessary part of the motor.
need β a requirement, necessary duty, or obligation: There is no need for you to go there.
want β to feel a need or a desire for; wish for: to want one's dinner; always wanting something new.
demand β If one thing demands another, the first needs the second in order to happen or be dealt with successfully.
adjective essential
vital β of or relating to life: vital processes.
indispensable β absolutely necessary, essential, or requisite: an indispensable member of the staff.
important β of much or great significance or consequence: an important event in world history.
crucial β If you describe something as crucial, you mean it is extremely important.
critical β If a person is critical or in a critical condition in hospital, they are seriously ill.
needed β necessary, required, or wanted (usually used in combination): a much-needed vacation.
