rep·ro·bate / ˈreprəˌbāt/ • n. an unprincipled person (often used humorously or affectionately). ∎ archaic Christian Theol. (esp. in Calvinism) a sinner who is not of the elect and is predestined to damnation.• adj. unprincipled (often used as a humorous or affectionate reproach): a long-missed old reprobate drinking comrade. ∎ Christian Theol., archaic (in Calvinism) predestined to damnation.• v. [tr.] archaic express or feel disapproval of: his neighbors reprobated his method of proceeding.DERIVATIVES: rep·ro·ba·tion / ˌreprəˈbāshən/ n.