old school

advocates or supporters of established custom or of conservatism: a military man of the old school.

Origin of old school

First recorded in 1790–1800

old-school, adjective

The Metropolitan Opera is the old-school Cadillac of arts institutions.

Inside the Metropolitan Opera’s Insane Year |Shawn E. Milnes |November 23, 2014 |DAILY BEAST
But old-school plants—the type that grow in the dirt—have also been vital to human progress.

Growth Stocks |The Daily Beast |October 17, 2014 |DAILY BEAST
The Spire rests on the same basic principal as the old-school fountains.

Font of Invention | |September 18, 2014 |DAILY BEAST
Rivers was an old-school trouper, fully immersed in pop culture for her comedy routine.

Joan Rivers: Our Last Interview |Tim Teeman |September 4, 2014 |DAILY BEAST

The 68-year-old actress follows an old-school routine from the Royal Canadian Air Force.

Helen Mirren Trains Like the Air Force; Kendall Jenner Denied Kim Kardashian at Her Shows |The Fashion Beast Team |July 29, 2014 |DAILY BEAST
It was only the absurd jealousy of the old-school Mussulmans that annihilated for ever the faculties of their wives.

In the Land of Mosques & Minarets |Francis Miltoun
The highbred conduct of Mr. Gwynn from the beginning had been worthy of him as an old-school English gentleman.

The President |Alfred Henry Lewis
Both Adah and Maria belong to that old-school class of proper feminine folk who never pick but always pluck flowers.

The House |Eugene Field
The special agent turned first to that primary command of the old-school detective when a crime is committed: "Find the woman."

Uncle Sam Detective |William Atherton Du Puy
He taught that “the most puzzling things of all to the old-school teleologists are the principia of the Darwinian.”

Encyclopaedia Britannica, 11th Edition, Volume 12, Slice 4 |Various

old school

mainly British a school formerly attended by a person

a group of people favouring traditional ideas or conservative practices