[ex.pert] adj [ME, fr. MF & L; MF, fr. L expertus, fr. pp. of experiri] (14c) 1 obs: experienced
2: having, involving, or displaying special skill or knowledge derived from training or experience syn see proficient -- ex.pert.ly adv -- ex.pert.ness n
[2]ex.pert n [F, fr. expert, adj.] (1535): one with the special skill or knowledge representing mastery of a particular subject [3]ex.pert vi (ca. 1889): to serve as an expert