guarded

adjective
  1. Cautious and having reservations; not revealing one's thoughts or feelings readily. adjective
    She gave a guarded response to the question, not wanting to reveal too much.
    His guarded demeanor made it difficult to understand his true intentions.
  2. Protected or watched over to prevent harm or unauthorized access. adjective
    The guarded facility was under constant surveillance to ensure security.
    The treasure was kept in a heavily guarded vault.