EXPERT

[noun] [C], [adjective] - (a person) having a high level of knowledge or skill; (a) specialistExperts have been called in to establish the cause of the plane crash.I enjoy radio programmes in which gardening experts give advice.My mother is an expert at dress-making (= she does it very well).William is an expert in/on (= has studied and knows a lot about) early Christian art.She's an expert swimmer.I thought your handling of the situation was expert.Gwen is expert at finding bargains.An expert system is a computer system which asks questions and gives answers that have been thought of by a human expert.