certify

certify — verb

1. to state clearly and formally, often in a signed document, that a particular fac

1.verbtransitive / intransitiveB2
Definition

to state clearly and formally, often in a signed document, that a particular fact, statement, or item is true, accurate, or meets an official standard

Example

Dr. Okafor certified that Priya was healthy enough to return to work after surgery.

certify + that-clause for stating a medical fact

A government official certified the building plans before the construction team broke ground.

certify + noun (document/plan) as officially approved

Common collocations
  • certify that
  • certify in writing
  • certify a document
  • certify a statement
  • certify results
Synonyms
  • confirm

    less formal; often verbal rather than written

  • verify

    focuses on checking facts against evidence

  • attest

    more formal; often used in legal or religious oaths

  • authenticate

    specifically about proving something is genuine, not counterfeit

Antonyms
  • disprove

    to show that something is false

  • refute

    to prove a statement is wrong through evidence

Grammar Patterns

certify + that-clause

certify + noun/pronoun + as + adj/noun

Usage Note

Common in legal, financial, and administrative contexts. Frequently used in the passive (something is certified) when the focus is on the document or statement rather than the person who certifies it.

Common Mistakes

The manager certified the news to be correct.
The manager confirmed the news to be correct.
certify is for official, documented statements; confirm is less formal and can be verbal.

2. to issue an official document or title recognising that a person has completed t

2.verbtransitiveB2
Definition

to issue an official document or title recognising that a person has completed the necessary training and is competent to practise a particular occupation

Example

Leila was certified as a yoga teacher after completing a six-month training course.

passive: be certified as [profession]

The clinic only hires dental assistants who are certified in infection control.

passive: be certified in [specialised field]

Common collocations
  • be certified as
  • be certified in
  • certified professional
  • certified teacher
  • certified nurse
Synonyms
  • accredit

    usually refers to organisations or programs rather than individuals

  • license

    focuses on official permission to practise, not just proof of training

  • qualify

    broader; can mean meeting requirements without a formal document

Grammar Patterns

be certified + as + noun (profession)

be certified + to-infinitive

be certified + in + noun (field)

Usage Note

Almost always used in the passive voice (be certified). The subject is a person who has completed training or passed an exam. The active form (The board certified Diego) is rarer and typically shifts focus to the issuing body.

Common Mistakes

I certified as a nurse last month.
I was certified as a nurse last month.
certify in this sense is almost always passive; use be certified.

3. to state officially, following a legal or medical process, that a person has a s

3.verbtransitiveC1
Definition

to state officially, following a legal or medical process, that a person has a serious mental illness and may need special care or supervision

Example

A judge certified Beatriz as mentally ill after two psychiatrists submitted detailed reports.

certify + noun + as mentally ill (legal-medical process)

The law requires two licensed doctors to certify a patient before any forced hospital stay.

passive construction with legal requirement

Common collocations
  • certify as mentally ill
  • certify a patient
  • certify insane
  • certify under the Mental Health Act
Synonyms
  • section

    British English; to officially detain someone in a psychiatric hospital under a section of the Mental Health Act

Grammar Patterns

certify + noun/pronoun + as mentally ill

certify + noun/pronoun + insane

Usage Note

Used in legal and medical contexts. The process typically involves professional psychiatric assessment and a formal court order. Distinguish from Sense 2: this sense is about mental health, not professional qualifications.

Word family

  • certification
    nounB2
  • certificate
    nounB2
  • certified
    adjectiveB2
  • certifier
    nounC1
  • certifiable
    adjectiveC1

Synonym discussion

Sense: verb/1

All four words involve establishing truth, but they differ in formality and scope. Confirm is the most general and least formal — you can confirm an appointment or a rumour without any official process. Verify adds the idea of checking facts against evidence; a scientist verifies experimental data. Attest is more formal and often implies a personal oath or signature, as when a witness attests to the validity of a will. Authenticate is the narrowest, focusing on proving that something is genuine rather than a copy or forgery, such as authenticating a painting or a signature. For everyday situations, confirm is safest; for official documents, certify (the headword) or attest fit best; for museum or security contexts, authenticate is the precise choice.

confirm ↗verify ↗attestauthenticate ↗

Common collocations

Nouns

Adverbs

Phrases

  • be certified
  • certify in writing

Prepositions

Etymology

LatinFrenchEnglish

Certify comes from Latin certificare, a combination of certus (“certain”) and facere (“to make”). It entered English through Old French certifier in the 1300s, originally meaning “to make certain or assure.” Over time it became tied to official written statements and formal qualifications.