confidential (Adjective) — Entrusted with private information and the confidence of another. ex. "a confidential secretary"
confidential (Adjective) — (of information) given in confidence or in secret. ex. "this arrangement must be kept confidential"
confidential (Adjective) — Denoting confidence or intimacy. ex. "a confidential approach" ex. "in confidential tone of voice"
confidential (Adjective) — The level of official classification for documents next above restricted and below secret; available only to persons authorized to see documents so classified.