necessary

necessary — adjective

1. Something that you must have, or that must happen, so that a particular result c

1.adjectiveA2
Definition

Something that you must have, or that must happen, so that a particular result can be achieved or a situation can exist.

Example

A valid passport is necessary if you plan to travel to most foreign countries.

n + be + necessary + if-clause

The hospital must buy the necessary equipment before the new wing opens.

the necessary + noun (equipment)

Common collocations
  • necessary equipment
  • necessary arrangements
  • necessary steps
  • necessary conditions
  • necessary for
  • absolutely necessary
Synonyms
  • essential

    stronger than 'necessary'; suggests something is at the very core of the activity

  • required

    more concrete and rule-based; often used for official needs

  • obligatory

    formal; refers to something demanded by a law or rule

Antonyms
  • unnecessary

    not needed; the most direct opposite

  • optional

    available to choose or not; not at all required

Grammar Patterns

it is necessary to + infinitive

necessary for + noun/gerund

necessary + noun

Usage Note

Often used in the pattern 'it is necessary to + verb' or 'it is necessary that + clause'. The opposite is 'unnecessary'.

Common Mistakes

It is necessary for me to going now.
It is necessary for me to go now.
after 'to', use the base form of the verb, not the -ing form.
It is necessary that he comes tomorrow.' (informal)
It is necessary that he come tomorrow.
in formal English, the subjunctive (no -s) is used after 'that'.

2. Used in negative statements and questions when you think something is wrong, exc

2.adjectiveB1
Definition

Used in negative statements and questions when you think something is wrong, excessive, or not worth doing.

Example

Was it really necessary to spend so much money on a hotel room?

question: Was it really necessary to...?

All this extra packaging is not necessary — the product would be fine without it.

not necessary for criticizing something

Common collocations
  • not necessary
  • really necessary (in questions)
  • was it necessary
  • hardly necessary
Synonyms
  • pointless

    stronger criticism; suggests the action has no purpose at all

  • unjustified

    formal; suggests the action has no reasonable basis

Grammar Patterns

not necessary

Is/Was it really necessary to...?

Usage Note

The disapproval is carried by context and tone, not by the word 'necessary' alone. 'Not necessary' can simply mean 'not required' in a neutral sense — the critical reading comes from the situation described.

Common Mistakes

It wasn't necessary to lock the door because there was nothing valuable inside.' (used neutrally, but may sound critical)
There was no need to lock the door.
for a neutral statement about lack of need, 'no need' avoids the possible critical tone.

3. Certain to happen because of the way a situation has developed; impossible to pr

3.adjectiveB2
Definition

Certain to happen because of the way a situation has developed; impossible to prevent or avoid.

Example

Higher prices are the necessary result when the cost of materials goes up.

the necessary result

The scientist accepted the failed experiment as a necessary step on the path to discovery.

Common collocations
  • necessary result
  • necessary consequence
  • necessary outcome
  • necessary part
  • necessary condition
Synonyms
  • inevitable

    more common in everyday language; means the same thing

  • unavoidable

    emphasises that no action could have prevented it

  • inescapable

    stronger and more dramatic; suggests something cannot be evaded

Antonyms

Grammar Patterns

necessary + noun (result/consequence/outcome)

Usage Note

This sense is most common with nouns like 'result', 'consequence', 'outcome', and 'part'. It is rarely used in everyday speech — 'inevitable' sounds more natural in casual contexts.

Idioms

a necessary evil

idiom

Something bad or unpleasant that you have to accept because it cannot be avoided and is needed for a larger purpose.

Mira sees paying taxes as a necessary evil that keeps the country running.

For many students, exams are a necessary evil that measures what they have learned.

necessary — noun

Word family

Synonym discussion

Sense: adjective/1

All four words describe something that is needed, but they differ in strength and context. 'Necessary' (A2) is the broadest and most neutral term — something is needed for a purpose. 'Required' (B1) is more rule-based: a course may be required for a degree regardless of whether the student finds it useful. 'Essential' (B1–B2) is stronger and suggests the thing is at the core of an activity: food is essential for survival, not merely necessary. 'Vital' (B2) is even stronger, implying that failure to have it would cause serious harm. In everyday speech, speakers often use these words interchangeably, but in formal or technical writing the differences matter: 'Please bring all the necessary documents' versus 'Water is vital for plant growth.'

necessary ↗essential ↗requiredvital ↗

Common collocations

Nouns

Adverbs

  • absolutely necessary
  • strictly necessary
  • really necessary
  • barely necessary

Phrases

  • if necessary
  • when necessary
  • where necessary
  • as necessary
  • only if necessary
  • it is necessary to

Prepositions

  • necessary for
  • necessary to

Etymology

LatinFrenchEnglish

The word 'necessary' entered English around the 1300s through Old French 'necessaire', which came from Latin 'necessarius' meaning 'unavoidable, indispensable'. The Latin root 'necesse' meant 'that which does not give way' — formed from 'ne-' (not) and 'cedere' (to yield, go away). So historically, something necessary was something that could not be avoided or moved aside. The modern sense of 'needed for a purpose' developed from this original idea of inescapable need.