* Necessary: absolutely essential; required.
* Necessity: the state or fact of being required or indispensable.
* Needless: unnecessary; not needed.
* Necessitate: to make something necessary.
* Necessitous: poor and in need.
* Necessitarian: one who believes that all events are predetermined and inevitable.
Note: The root word "necess" comes from the Latin word "necesse," meaning "necessary."