팔정도 (八正道)의 여섯 번째. 속된 생각을 버리고 선행을 닦아 오로지 불도 (佛道)에만 열중 하는 것. 정진을 일반정진 (8-10시간), 가행정진 (加行精進) (12-14시간), 용맹정진 (勇猛精進) (18시간 이상), 무문관정진 (無門關精進) (몇 개월 동안 독방정진) 등으로 구분하기도 함

Viriya: Great striving or effort, zealous practice, rigorous self-discipline, great devotion, exertion, zeal, unfaltering endeavor. The sixth of the Noble Eightfold Path or Truth. There are several grades of exertion: 1) Ordinary (8-10 hours), 2) Progressive (12-14 hours), 3) Ferocious (18 hours or more), 4) Locking oneself in a small room, never coming out of the room for months, and taking food only through a small hole in the door.