passive immunity passive air defense • passively · · · Info · Definitions · Characters · · passive immunity · · Text Common · · Latin · · Scripts 16 · · Length 6 · · Syllables Definitions · · · (noun) 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). Synonyms: passive immunity. · · Noun Definition 1 Characters · · space U+0020 a latin small letter a U+0061 e latin small letter e U+0065 i latin small letter i U+0069 m latin small letter m U+006D n latin small letter n U+006E p latin small letter p U+0070 s latin small letter s U+0073 t latin small letter t U+0074 u latin small letter u U+0075 v latin small letter v U+0076 y latin small letter y U+0079