Definition of "gnostic"

Maggie (as she is usually called) says she is constantly amazed at Kast's "almost gnostic outlook" on life.

1988 September 16, Robert McClory, “Heal Thy Neighbor”, in Chicago Reader‎

I said you were a d—d gnostic fellow.

1823 December 23 (indicated as 1824), [Walter Scott], St Ronan’s Well. […], volumes (please specify |volume=I to III), Edinburgh: […] [James Ballantyne and Co.] for Archibald Constable and Co.; London: Hurst, Robinson, and Co.