Platonist

From Latin Platonista, from Plato + -ista, equivalent to Plato + -ist

Platonist (plural Platonists)

1. A member of the philosophical school of thought established by Plato; a believer in Platonism.
   • 1549, Hugh Latimer, The Seconde Sermon... Preached before the Kynges Maiestie:

     [St Augustine of Hippo] became of a Maniche, and of a platoniste a good christian.

2. One who holds similar beliefs, particularly that abstract ideas are real.
   • 1992 March 2, Richard Preston, The New Yorker, "The Mountains of Pi":

     I suspect that in their hearts most working mathematicians are Platonists, in that they take it as a matter of unassailable if unprovable fact that mathematical reality stands apart from the world, and is at least as real as the world, and possibly gives shape to the world, as Plato suggested.

3. (rare, obsolete) A platonic lover.

• “Platonist, n.”, in OED Online ⁠, Oxford: Oxford University Press, launched 2000.