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

That way, McIlroy said, it felt second nature to Nicklaus when the event actually began.

From The Wall Street Journal • Apr. 13, 2026

It takes an exceptional piece of art to inspire audiences to think twice about what comes as second nature, to choose compassionate contemplation over ardent debate.

From Salon • Apr. 9, 2026

“He wanted the rules to be just second nature to him,” Harbert said.

From Los Angeles Times • Jan. 6, 2025

These things are just kind of second nature to us.

From BBC • Feb. 6, 2024

“Running is second nature to me, it’s not something I have to think about.”

From "Twilight" by Stephenie Meyer