Necessity
Essential requirement
Synonyms: Essential requirement, indispensable thing/item, requisite, fundamental, sine qua non, indispensability, needfulness, prerequisite, essential, necessary, basic, desideratum, and need.
Inevitability
Synonyms: Inevitability, certainty, inexorability, unavoidability, inescapability, and ineluctability.
Need
Synonyms: Force/pressure of circumstance, obligation, exigency, emergency, force majeure, need, call, crisis, and urgency.
Essential requirement
Synonyms: Essential requirement, indispensable thing/item, requisite, fundamental, sine qua non, prerequisite, essential, necessary, basic, and desideratum.
Example Sentences
Water is a necessity for survival.
Education is a necessity for success.
In emergencies, communication becomes a necessity.
Food and shelter are basic necessities.