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: as, a stealthy foe; characterized by concealment; furtive: as, a stealthy proceeding; a stealthy movement.

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