/ Thesaurus / P Synonyms of passive immunity Find synonyms for: Noun1. passive immunity, acquired immunityusage: an impermanent form of acquired immunity in which antibodies against a disease are acquired naturally (as through the placenta to an unborn child) or artificially (as by injection of antiserum)WordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: rustic Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language