The almost universal pronunciation of sacrilegious as
[sak-ruh-lij-uh s] /ˌsæk rəˈlɪdʒ əs/ (Show IPA) is the result of folk etymology—modifying the pronunciation of an unfamiliar word so that it conforms to a more familiar one—in this case religious. Etymologically, sacrilegious has no direct relationship to religious. The historical pronunciation
[sak-ruh-lee-juh s] /ˌsæk rəˈli dʒəs/ occurs in American English, though not in British English, and criticism of the newer pronunciation has almost disappeared.
British Dictionary definitions for sacrilegious
sacrilegious
/ˌsækrɪˈlɪdʒəs/
adjective
1.
of, relating to, or involving sacrilege; impious
2.
guilty of sacrilege
Derived Forms
sacrilegiously, adverb sacrilegiousness, noun
Word Origin and History for sacrilegious
adj.
mid-15c., from Latin sacrilegiosum, from sacrilegium (see sacrilege). As a noun, "one who commits a sacrilege," early 14c. Related: Sacrilegiously; sacrilegiousness.