diagnostician|ˌdaɪəgnɒˈstɪʃən| [f. as prec. + -ian.] One who is skilled in diagnosis. 1866A. Flint Princ.Med. (1880) 108 The mental qualifications of the skilful diagnostician.1894Pop.Sci. Monthly XLIV. 478 By the skilled teacher I now mean the one who is an expert diagnostician of powers.