/ Thesaurus / I Synonyms of immaculate conception Find synonyms for: Noun1. Immaculate Conception, December 8, holy day of obligationusage: Roman Catholic holy day first celebrated in 18542. Immaculate Conception, Immaculate Conception of the Virgin Mary, religious doctrine, church doctrine, gospel, creedusage: (Christianity) the Roman Catholic dogma that God preserved the Virgin Mary from any stain of original sin from the moment she was conceivedWordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: penury Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language