secret intelligence service secretin • secretion · · · Info · Definitions · Characters · · secret intelligence service · · Text Common · · Latin · · Scripts 27 · · Length 8 · · Syllables Definitions · · · (noun) the government agency in the United Kingdom that is responsible for internal security and counterintelligence overseas. Synonyms: Secret Intelligence Service, MI, Military Intelligence Section 6. · · Noun Definition 1 Characters · · space U+0020 c latin small letter c U+0063 e latin small letter e U+0065 g latin small letter g U+0067 i latin small letter i U+0069 l latin small letter l U+006C n latin small letter n U+006E r latin small letter r U+0072 s latin small letter s U+0073 t latin small letter t U+0074 v latin small letter v U+0076