late 14c., seintefien "to consecrate, set apart for sacred use;" c. 1400, "to render holy or legitimate by religious sanction;" from Old French saintefier "sanctify" (12c., Modern French sanctifier), from Late Latin sanctificare "to make holy," from sanctus "holy" (see saint (n.)) + combining form of facere "to make, to do" (from PIE root *dhe- "to set, put").
The form was altered in English c. 1400 to conform to Latin. From 1520s (Tyndale) as "to free from sin." The transferred sense of "to render worthy of respect" is from c. 1600. Related: Sanctified; sanctifying.
updated on December 06, 2021