turn over a new leaf

To change one's behavior, usually in a positive way. Jason has really turned over a new leaf—he hasn't been in the slightest bit of trouble in months.

Fig. to begin again, fresh; to reform and begin again. (Fig. on turning to a fresh page. The leaf is a page—a fresh, clean page.) I have made a mess of my life. I'll turn over a new leaf and hope to do better. Why don't you turn over a new leaf and surprise everyone with your good characteristics?

Make a fresh start, change one's conduct or attitude for the better, as in He promised the teacher he would turn over a new leaf and behave himself in class. This expression alludes to turning the page of a book to a new page. [Early 1500s]

COMMON If someone has turned over a new leaf, they have started to behave in a better way than before. Note: The `leaf' in the last two expressions is a page of a book. While Eddie has turned over a new leaf, his brother can still be spotted in the bars along Sunset Strip. Both men have agreed to turn over a new leaf in their relations with each other. Compare with turn the page.

To make a new start; to improve one’s conduct or outlook. The leaf in question means the page of a book, and the term dates from the sixteenth century. Sometimes “new” was omitted, as in John Heywood’s Proverbs (1546): “Naie she will tourne the leafe.” But Roger Ascham already had the modern version (The Scholemaster, 1570): “Except soch men thinke them selves wiser than Cicero . . . they must be content to turne a new leafe.”