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

She struck more chords, her fingers finding the keys with the second-nature sureness, learned in her months of dreary practice.

From Project Gutenberg

Telling lies is a fault in a boy, an art in a lover, an accomplishment in a bachelor, and second-nature in a married man.

From Project Gutenberg