Synonyms/Hypernyms (Ordered by Estimated Frequency) of noun necessity

2 senses of necessity

Sense 1
necessity -- (the condition of being essential or indispensable)
       => need, demand -- (a condition requiring relief; "she satisfied his need for affection"; "God has no need of men to accomplish His work"; "there is a demand for jobs")

Sense 2
necessity, essential, requirement, requisite, necessary -- (anything indispensable; "food and shelter are necessities of life"; "the essentials of the good life"; "allow farmers to buy their requirements under favorable conditions"; "a place where the requisites of water fuel and fodder can be obtained")
       => thing -- (a separate and self-contained entity)