/ Thesaurus / J Synonyms of jack o lantern Find synonyms for: Noun1. jack-o-lantern fungus, jack-o-lantern, jack-a-lantern, Omphalotus illudens, agaricusage: a large poisonous agaric with orange caps and narrow clustered stalks; the gills are luminescentWordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: inutiae Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language