familiarity

American  

[fuh-mil-ee-ar-i-tee, -mil-yar-] / fəˌmɪl iˈær ɪ ti, -mɪlˈyær- /

noun

plural

familiarities

1. thorough knowledge or mastery of a thing, subject, etc.

2. the state of being familiar; friendly relationship; close acquaintance; intimacy.

3. an absence of ceremony and formality; informality.

   Synonyms:

   unconstraint

4. freedom of behavior justified only by the closest relationship; undue intimacy.

   Synonyms:

   license, freedom, liberty

5. Often familiarities. an instance of such freedom, as in action or speech.

6. a sexual liberty or impropriety.

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familiarity British  

/ fəˌmɪlɪˈærɪtɪ /

noun

1. reasonable knowledge or acquaintance, as with a subject or place

2. close acquaintanceship or intimacy

3. undue intimacy

4. (sometimes plural) an instance of unwarranted intimacy

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Other Word Forms

• overfamiliarity noun
• prefamiliarity noun

Etymology

Origin of familiarity

1350–1400; Middle English familiarite (< Anglo-French ) < Latin familiāritās intimacy. See familiar, -ity

Explanation

Familiarity is the state of knowing something very well. It's also a casual way of behaving. Your familiarity with your best friend means that you can say whatever you want around her. Familiarity is from the Latin word familiaritatem for "intimacy, friendship.” Familiarity is used in situations that people know well. A painter has a familiarity with brushes and canvas. When there’s familiarity with a task, people aren’t stressed, because they’ve done it before. This word also refers to a casual way of acting: if you hug someone, it shows familiarity. That kind of familiarity is the opposite of aloofness and formality.

Example Sentences

Demonstrating familiarity with the tools required for things like programming, graphic design and data-management is no longer enough when AI is able to take on those sorts of tasks.

From MarketWatch • Apr. 11, 2026

“There has to be some kind of familiarity in the characters and relationships, but also growth — something new that justifies coming back.”

From Los Angeles Times • Apr. 9, 2026

The findings also highlight a clear difference between familiarity with organ donation and brain donation.

From Science Daily • Apr. 8, 2026

What happened next had an eerie feeling of familiarity about it.

From Slate • Mar. 29, 2026

And so they spent hours there, watching the birds come and go, feeding them from their palms, exulting in the familiarity that allowed the birds to land on their arms and shoulders.

From "Zeitoun" by Dave Eggers

Related Words

• boldness
• closeness
• freshness
• intimacy