Expert

(14), a. [Lat. expertus, p. p. of experiri; Fr. expert, Pr. expert, espert, Sp. & Pg. experto, It. esperto, sperto. See EXPERIENCE.] Taught by use, practice, or experience; well instructed; having familiar knowledge; having a facility of operation or performance from practice; skillful; as, an expert philosopher; an expert surgeon; expert in chess or archery. “A valiant and most expert gentleman.” Shak. Syn.—Adroit; dexterous; skillful; ready; prompt.

n. An expert, skillful, or practiced person; one who has skill, experience, or peculiar knowledge on certain subjects of inquiry in science, art, trade, or the like; a scientific or professional witness.