au fait

IPA/ˌəʊ ˈfeɪ/
IPA/ˌəʊ ˈfeɪ/

au fait — adjective

1. knowing a lot about a particular subject or activity because you have learned ab

1.adjectiveC1
Definition

knowing a lot about a particular subject or activity because you have learned about it or have recent direct experience of it

Example

Baraka was completely au fait with the new accounting system after just two days.

collocation: completely au fait with [system]

The investment team needs someone au fait with current market trends in Asia.

register: formal; pattern: au fait with [topic]

Common collocations
  • completely au fait with
  • fully au fait with
  • perfectly au fait with
  • become au fait with
  • keep / stay au fait with
  • au fait with the details / system / trends / rules
Synonyms
  • familiar with

    more common and less formal; works in everyday conversation

  • conversant with

    equally formal; common in professional writing

  • well-versed in

    stronger emphasis on deep understanding through study or practice

Antonyms

Grammar Patterns

be + au fait + with + noun phrase

stay + au fait + with + noun phrase

Usage Note

Always used as a predicative adjective after 'be,' 'become,' 'keep,' or 'stay.' Never placed before a noun — you cannot say 'an au fait expert.' The preposition that follows is always 'with,' never 'about' or 'of.'

Common Mistakes

She is au fait about the project.
She is au fait with the project.
The correct preposition after 'au fait' is 'with,' not 'about' or 'of.'
He is an au fait lawyer.
He is au fait with corporate law.
'Au fait' cannot go before a noun; it only works after a linking verb like 'be' or 'stay.'

2. showing polished social behaviour and good manners, as if you know exactly how t

2.adjectiveC2
Definition

showing polished social behaviour and good manners, as if you know exactly how to act in formal or elegant situations

Example

The young diplomat was perfectly au fait, charming everyone at the ambassador's dinner party.

old-fashioned use; register: formal; collocation: perfectly au fait

Talia's grandmother taught her to be au fait at formal dinners, from manners to conversation.

Common collocations
  • perfectly au fait
  • quite au fait
Synonyms
Antonyms
  • awkward

    neutral opposite focusing on social clumsiness

  • gauche

    formal French loanword with a similar register

Grammar Patterns

be + au fait

Usage Note

This sense is now quite old-fashioned and rarely used in modern English. The 'familiar with' sense (sense 1) is the only common use today. When you encounter this social-competence meaning, it is typically in historical fiction or descriptions of upper-class etiquette.

Synonym discussion

Sense: adjective/1

All three describe knowing something well, but they differ in register and emphasis. 'Familiar with' is the most common and neutral — you can use it in any setting ('She is familiar with the software'). 'Conversant with' is more formal and suggests the ability to discuss or work with a topic competently ('He is conversant with international trade law'). 'Well-versed in' carries a stronger implication of deep, studied knowledge ('They are well-versed in classical Chinese poetry'). 'Au fait' sits closest to 'conversant with' in formality but adds a slight French-derived elegance; it is most natural when describing someone who has kept up-to-date with a specific subject or skill through recent exposure.

familiar withconversant withwell-versed in

Common collocations

Nouns

Adverbs

Phrases

  • be au fait with
  • become au fait with
  • keep au fait with
  • stay au fait with

Prepositions

Etymology

FrenchEnglish

Borrowed directly from French in the mid-18th century. In French, 'au fait' literally means 'to the fact' (au = to the, fait = fact or deed). The English meaning developed from the idea of being 'up to the facts' — that is, fully informed about a subject. In modern French, the same phrase can also mean 'by the way,' but English kept only the 'informed' sense.