uncommunicative, incommunicative

not inclined to talk or give information or express opinions

• blank — void of expression
• close, closelipped, closemouthed, secretive, tightlipped — inclined to secrecy or reticence about divulging information
• deadpan, expressionless, impassive, poker-faced, unexpressive — deliberately impassive in manner
• guarded, noncommittal, unrevealing — very reluctant to give out information
• incommunicado — without the means or right to communicate
• inexpressive — not expressive
• mum, silent — failing to speak or communicate etc when expected to
• unpronounceable, unutterable — very difficult to pronounce correctly