Paraskaragrihyasutra 2.5.32

2.5.32

trayaḥ snātakā bhavanti vidyāsnātako vratasnātako vidyāvratasnātaka iti \32\

There are three (kinds of) Snâtakas: a Vidyâ-snâtaka (i.e. a Snâtaka by knowledge), a Vrata-snâtaka (i.e. a Snâtaka by the completion of his vows), and a Vidyâ-vrata-snâtaka (i.e. a Snâtaka both by knowledge and by the completion of his vows).