Disputant

n. One who disputes; one who argues in opposition to another; one appointed to dispute; a controvertist; a reasoner in opposition. A singularly eager, acute, and pertinacious disputant. Macaulay.

a. [Lat. disputans, p. pr. of disputare; Fr. disputant, It. disputante. See DISPUTE, v.] Disputing; engaged in controversy. Milton.