proficientn.[L. proficiens, -entis, p. pr. of proficere to go forward, make progress; pro forward + facere to make. See Fact, and cf. Profit, ()] One who has made considerable advances in any business, art, science, or branch of learning; an expert; an adept; as, proficient in a trade; a proficient in mathematics, music, etc.()a. Well advanced in any branch of knowledge or skill; possessed of considerable acquirements; well-skilled; versed; adept,()