Affixes

Diagnosis (Greek dia, apart) is the identification of an illness by examining its symptoms, while a prognosis (Greek pro‑, before) is a forecast of the likely outcome of a disease. Gnosis itself refers especially to spiritual knowledge. Other examples are stereognosis, the ability to perceive the form of solid objects by touch, and telegnosis, the psychic perception of events happening at a distance. Adjectives are formed using ‑gnostic: diagnostic, gnostic (hence agnostic, from Greek a‑, not or without, relating to a belief that nothing is known or can be known of the nature of God). All these can also be nouns.