passive air defense passive • passive immunity · · · Info · Definitions · Characters · · passive air defense · · Text Common · · Latin · · Scripts 19 · · Length 5 · · Syllables Definitions · · · (noun) air defense by the use of deception or dispersion or protective construction. Synonyms: passive air defense. · · Noun Definition 1 Characters · · space U+0020 a latin small letter a U+0061 d latin small letter d U+0064 e latin small letter e U+0065 f latin small letter f U+0066 i latin small letter i U+0069 n latin small letter n U+006E p latin small letter p U+0070 r latin small letter r U+0072 s latin small letter s U+0073 v latin small letter v U+0076