The Collaborative International Dictionary
Pyrrhonic
Pyrrhonean \Pyr*rho"ne*an\, Pyrrhonic \Pyr*rhon"ic\, a. [L. Pyrrhon[^e]us: cf. F. pyrrhonien.] Of or pertaining to pyrrhonism.
Douglas Harper's Etymology Dictionary
Pyrrhonic
1590s, "pertaining to Pyrrho," skeptic philosopher of Elis (c.360-c.275 B.C.E.), who held the impossibility of attaining certainty of knowledge. Related: Pyrrhonism; Pyrrhonist.