Definition of requisite:
at all costs, vital, necessitous, essence, undeniable, essential, integral, without fail, requirement, burning issue/question, required, feature, basic, precondition, of necessity, necessary, infallible, demand, demanded, core, element, important, basis, need, necessity, sine qua non, key, priority, staple, unavoidable, needed, important, concern, needful, critical, must-have, study at essential, all-important.
- obligatory (part of speech: adjective)
- requirement (part of speech: noun)
- required (part of speech: adjective)
- "Perfect Behavior A Guide for Ladies and Gentlemen in all Social Crises", Donald Ogden Stewart.
- "Middy and Ensign", G. Manville Fenn.
- "Mr. Midshipman Easy", Captain Frederick Marryat.