secretive
se-cre-tive
adjective
Inclined to hide one's thoughts, feelings, or actions from others.
"She was very secretive about her plans."
adjective
Characterised by or involving the keeping of secrets.
"The organisation was highly secretive."
Thesaurus
Synonyms: closemouthed, uncommunicative, incommunicative, close, closelipped, tightlipped