Necessary

Required because it is essential to a good result.

Reach for it when stating that a condition or action is required for the intended result

Clear consent is necessary before the researchers begin any interview.

• everyday

  needed

  plain language should express a real need

  not when Needed can sound subjective without naming the goal.

• warm

  vital

  importance to survival or success deserves emphasis

  not when Vital is emotive and often stronger than necessary.

• professional

  essential

  the result cannot succeed without it

  not when Essential is stronger than merely required by a rule.

• professional

  required

  a rule, specification, or authority mandates it

  not when Required does not prove practical importance.

• formal

  indispensable

  nothing else can replace the contribution

  not when Indispensable can overstate a person's uniqueness.

• formal

  requisite

  a formal prerequisite is being identified

  not when Requisite is stiff in ordinary guidance.

• literary

  unavoidable

  circumstances leave no practical alternative

  not when Unavoidable concerns choice, not usefulness.

• optional
• unnecessary
• dispensable

• necessary step

  Consent is a necessary step before any interview begins.

• when necessary

  The mediator paused the meeting when necessary.

• absolutely necessary

  Only absolutely necessary repairs were scheduled during nesting season.