GNOSTIC, a believer in a mystical religious doctrine of spiritual knowledge.
As opposed to an AGNOSTIC, someone who professes not to know.
In the word AGNOSTIC, the A- prefix has sustained the phonetic life of the letter G. The G in GNOSTIC, lacking this prefixation, has fallen away, slowly and silently. Yet it lingers on in text, an orthographic fossil.
Notice how GNOSTIC, AGNOSTIC, PROGNOSTIC and DIAGNOSTIC, each represent a particular state related to knowledge. They all stem from GNOSIS, Greek for investigate or know.
It must be that the English word KNOW came pretty much directly from the Greek stem GNOSIS and the transliterative anglicizing process swapped a G for a K and added a W on the end. Gno what I mean?
Another word, NOBLE, meaning highborn, distinguished, known.
NOBLE has no G to speak of but it too finds its root in GNOSIS.
The G in (G)NOBLE has been completely eroded, both phonetically and orthographically.
NOBLE’s phantom G only reveals itself via a reflection in NOBLE’s antonymic mirror, IGNOBLE.
We can see that in the word IGNOBLE, the I- prefix has secured the orthographic and phonetic vitality of the G, just as the A- prefix has done in AGNOSTIC.