Digha Nikaya 1:468
SUJATOIdhānanda, bhikkhu kāye kāyānupassī viharati atāpī sampajāno satimā, vineyya loke abhijjhādomanassaṁ.
It’s when a mendicant meditates by observing an aspect of the body—keen, aware, and mindful, rid of covetousness and displeasure for the world.