Platonist
/ˈpleɪtənɪst/
Definition 1 of 1
Pro Tip 1/3Philosophical Belief
The term relates to supporting Plato's ideas, not just liking his work generally. 
As a Platonist, she subscribes to the belief in a realm of ideal forms.
Pro Tip 2/3Academic Term
Most often used in academic or philosophical discussions, less in casual talk. 
His thesis showcases his stance as a modern Platonist.
Pro Tip 3/3Specific Philosophy
Understand that it relates specifically to Plato's philosophy, not ancient Greek philosophy as a whole. 
She wrote a paper comparing Aristotelians and Platonists.