Source : Webster's Revised Unabridged Dictionary (1913)

Neoplatonism \Ne`o*pla"to*nism\, n. [Neo- + Platonism.]
   A pantheistic eclectic school of philosophy, of which
   Plotinus was the chief (A. D. 205-270), and which sought to
   reconcile the Platonic and Aristotelian systems with Oriental
   theosophy. It tended to mysticism and theurgy, and was the
   last product of Greek philosophy.

Source : WordNet®

Neoplatonism
     n : a system of philosophical and religious doctrines composed
         of elements of Platonism and Aristotelianism and oriental
         mysticism; its most distinctive doctrine holds that the
         First Principle and source of reality transcends being
         and thought and is naturally unknowable; "Neoplatonism
         was predominant in pagan Europe until the 6th century";
         "Neoplatonism was a major influence on early Christian
         writers and on later medieval and Renaissance thought and
         on Islamic philosophy"