second nature

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.

second nature

noun

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

Word History and Origins

Origin of second nature¹

First recorded in 1655–65

Idioms and Phrases

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.

Example Sentences

“It was very much second nature to us.”

From Los Angeles Times

“The way that she thinks and moves and speaks and acts and behaves is almost second nature because of how long I’ve lived in her,” Ramsey says.

From Los Angeles Times

But what might’ve felt unnatural to him not that long ago, he says, is starting to feel like second nature.

From Los Angeles Times

"The difficulty is that our phones have become so much a part of our day-to-day life that recording and sharing has become second nature," she added.

From BBC

"When I was younger, to be fair, it was second nature", he said, adding that he other fans "took it for granted in a way".

From BBC