ensure

ensure — verb

1. to take action so that a particular result is achieved or a situation definitely

1.verbtransitiveB2
Definition

to take action so that a particular result is achieved or a situation definitely happens, especially by preventing possible problems

Example

Eli checked the windows twice to ensure they were all locked before leaving.

ensure + that-clause (that omitted)

A backup generator was installed to ensure the factory could keep running during blackouts.

passive to highlight purpose

Common collocations
  • ensure safety
  • ensure quality
  • ensure compliance
  • ensure success
  • ensure accuracy
  • ensure proper functioning
Synonyms
  • guarantee

    Stronger, often involves a formal or explicit promise; 'ensure' focuses on taking practical steps rather than making a promise.

  • make sure

    More informal and conversational; used in everyday speech where 'ensure' sounds more formal.

  • certify

    Formal and official; implies a written or documented confirmation rather than a practical action.

Antonyms
  • neglect

    Means to fail to take care of something, which can lead to an uncertain or negative outcome.

  • jeopardize

    Means to put something at risk, the opposite of making it certain and safe.

Grammar Patterns

ensure + noun phrase

ensure + that-clause

ensure (that) + clause (informal, that omitted)

Usage Note

Frequently followed by a that-clause or a noun phrase specifying the outcome. The subject is typically a person, an organization, or a precautionary measure. Unlike 'assure', 'ensure' takes a direct object that refers to an event or situation, not a person.

Common Mistakes

I want to ensure you that the package will arrive.
I want to assure you that the package will arrive.
'ensure' means to make something certain; 'assure' means to remove someone's doubts by telling them something is true.
Please ensure me that the doors are locked.
Please ensure that the doors are locked.
'ensure' does not take an indirect object. The thing made certain, not the person, is the direct object.

Word family

Synonym discussion

Sense: verb/1

All four words relate to certainty, but they differ in what is made certain and how. 'Ensure' focuses on taking practical steps to make sure something happens — you check, prepare, or install safeguards. 'Insure' primarily means to buy financial protection against loss (insure a car, insure a house), though American English sometimes uses it interchangeably with 'ensure'. 'Assure' targets a person's feelings: you tell someone something is true to remove their doubt ('I assure you the train is on time'). 'Guarantee' carries a formal promise, often written or contractual, that a result will happen or a product will work. Example: 'The mechanic ensured the brakes were working (practical check); the company insures the building against fire (financial protection); the pilot assured passengers the flight was safe (removed worry); the store guarantees the laptop for two years (formal promise).'

ensure ↗insure ↗assure ↗guarantee

Common collocations

Nouns

  • measures
  • steps
  • procedures
  • precautions
  • systems

Adverbs

  • virtually ensure
  • practically ensure
  • effectively ensure
  • thereby ensure

Phrases

  • to ensure that
  • in order to ensure
  • help ensure
  • help to ensure

Etymology

LatinOld FrenchMiddle EnglishModern English

The word 'ensure' comes from the Old French 'enseurer', which combines 'en-' (to make) and 'seür' (sure, secure). The French word traces back to the Latin 'indurare', meaning 'to make hard or firm'. The original sense of 'making firm' gradually shifted to 'making certain' in Middle English, where it was also spelled 'ensure' and 'insure' interchangeably before the two spellings diverged in meaning.