A2adjective1K

Necessary

UK /["/ˈnesəsəri/"]/US /["/ˈnesəseri/"]/

Definition

that is needed for a purpose or a reason

In simple words: Something that must be done or is very important.

Examples

  • It is necessary to drink water to stay hydrated.
  • In some cases, it is necessary to use a seatbelt in the car.
  • Is it really necessary to wake up so early?
  • The necessary materials for the project were delivered yesterday.
  • Only bring what is necessary for the trip.

Usage notes

Used in both spoken and written language. Appropriate in academic and everyday contexts, but not overly casual. Avoid using it in informal conversations where simpler words like 'needed' might fit better.

Grammar pattern

necessary + to + verb / necessary + noun

Memory hint

Think of 'necessary' as 'need-sary' — you need it, so it’s necessary.

Collocations

  • appear
  • be
  • prove
  • really
  • strictly
  • absolutely
  • for
  • if necessary
  • as necessary
  • when necessary

Synonyms

  • essential
  • inevitable

Antonyms

  • unnecessary
  • optional
  • nonessential

Common mistakes

  • Confused with 'necessity' — 'necessary' describes something needed, whereas 'necessity' is a noun.
  • Using 'necessary' with an incorrect verb form — remember it usually pairs with 'to' before a verb.
  • Omitting 'to' before the verb when using it in a phrase.