mid-15c., sacrilegiose, "committing sacrilege, guilty of sacrilege," from Latin sacrilegiosum, from sacrilegium (see sacrilege). The sense of "profane, impious, involving sacrilege" is by 1620s. Earlier as a noun, "one who commits a sacrilege" (early 14c.). Related: Sacrilegiously; sacrilegiousness.

"sacrilegious treatment, act of diverting from a hallowed purpose or use," 1717, noun of action from desecrate (v.).