stealthy

Marked by or acting with quiet, caution, and secrecy intended to avoid notice. synonym: secret.

Acting by stealth; sly; secretive in act or manner; employing concealed methods.

Done by stealth; accomplished clandestinely; unperceived; secret; furtive; sly.

Characterized by or resembling stealth or secrecy.

Marked by quiet and caution and secrecy; taking pains to avoid being observed.