hush–hush 
/ˈhʌʃˌhʌʃ/ adjective
/ˈhʌʃˌhʌʃ/ adjective [more hush–hush; most hush–hush] : kept secret : known only to a few people
▪ He wants to keep the relationship hush-hush. ▪ She works for a hush-hush government agency.
▪ He wants to keep the relationship hush-hush. ▪ She works for a hush-hush government agency.
