Necessary
Essential
Synonyms: Obligatory, required, mandatory, demanded, called for, essential, vital, incumbent, requisite, compulsory, imperative, needed, needful, indispensable, of the essence, and de rigueur.
Inevitable
Synonyms: Inevitable, certain, inescapable, ineluctable, destined, predestined, unavoidable, sure, inexorable, fated, predetermined, and preordained.
Example Sentences
Water is necessary for human survival.
Exercise is necessary for good health.
Proper planning is necessary for success.
Safety measures are always necessary.
It’s necessary to stay focused.