secretive       
adjective  mainly disapproving uk/ˈsiː.krə.tɪv/ us/ˈsiː.krə.t̬ɪv/
 遮遮掩掩的;守口如瓶的
People who are secretive hide their feelings, thoughts, intentions, and actions from other people.
  He's being very secretive about his new girlfriend. 关于他的新女朋友他总是遮遮掩掩的。 
 Synonyms: close (SECRETIVE)tight-lipped
Compare: keep mum