Breadcrumb Home > Thesaurus > U Synonyms of ufo Find synonyms for: Noun 1. unidentified flying object, UFO, flying saucer, apparition, phantom, phantasm, phantasma, fantasm, shadow usage: an (apparently) flying object whose nature is unknown; especially those considered to have extraterrestrial origins WordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved.Definition and meaning of ufo (Dictionary) TrendingHere are the facts and trivia that people are buzzing about. Jewish Holidays, 2010-2030 (A.M. 5770-5791) Western Christian Holidays, 2010-2030 12 Steps to a New Year New Year's Resolution to Slim Down? Martin Luther King Speeches Books of the Bible: Old Testament Books in Order ✖ Related Content Daily Word Quiz: catalpa Analogy of the Day: Today’s Analogy Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language