expert
Cross references: 1. proficient 1. ex.pert \'ek-.sp*rt, ik-'\ aj [ME, fr. MF & L; MF, fr. L expertus, fr. pp. of experiri] obs 1: EXPERIENCED 2: having, involving, or displaying special skill or knowledge derived fro m training or experience - ex.pert.ly av 2. ex.pert \'ek-.sp*rt\ n [F, fr. expert, adj] : one who has acquired special skill in or knowledge of a particular subje ct : AUTHORITY 3. ex.pert \'ek-.sp*rt\ vt : to serve as an expert for : to serve as an expert