second nature

American  

noun

1. an acquired habit or tendency in one's character that is so deeply ingrained as to appear automatic.

   Neatness is second nature to him.

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second nature British  

noun

1. a habit, characteristic, etc, not innate but so long practised or acquired as to seem so

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second nature Idioms  

1. A habit or mode of behavior so long practiced that it seems innate, as in Driving in heavy traffic is second nature to Chris. This expression is a shortened form of an ancient proverb, Custom (or usage) is a second nature, first recorded in 1390. It alludes to the fact that very frequently repeating something makes it seem completely natural or inborn.

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Etymology

Origin of second nature

First recorded in 1655–65

Example Sentences

It eventually became second nature for her and the cast, she says.

From Los Angeles Times • Feb. 26, 2026

Taking part in a panel discussion about male suicide with host Greg James, he said that would help open discussions "become second nature to us all" and reflected on his own strategies for processing emotions.

From BBC • Feb. 18, 2026

He's still a teenager whose pace and ability to ghost past defenders is second nature to him.

From BBC • Oct. 12, 2025

The idea is that once it comes to gametime, passes can come from any direction and hauling them in becomes second nature because it’s such a familiar process.

From The Wall Street Journal • Oct. 2, 2025

It’s not second nature like it is for me and Zarra.

From "Black Brother, Black Brother" by Jewell Parker Rhodes