philosopher XIV. — AN. philo-, filosofre, var. of (O)F. philosophe — L. philosophus — Gr. philósophos ‘lover of wisdom’, f. PHILO- + base of sophós wise.
So philosophic XVII, philosophical XIV. — late L. philosophicus. philosophize XVI. corr. in use to F. philosopher, L. philosophārī, Gr. philosopheîn. philosophy (-Y3) XIII.

philosopher a person engaged or learned in philosophy, especially as an academic discipline.
philosopher kings in the political theory of Plato, the elite whose knowledge enables them to rule justly.
philosopher's stone a mythical substance supposed to change any metal into gold or silver and, according to some, to cure all diseases and prolong life indefinitely. Its discovery was the supreme object of alchemy.

phi·los·o·pher / fəˈläsəfər/ • n. a person engaged or learned in philosophy, esp. as an academic discipline.