a person with special knowledge, skill or training in something a computer/medical expert expert (at/in/on something) an expert in child psychology an expert on modern literature expert (at/in/on doing something) He's an expert at getting his own way. Don't ask me—I'm no expert! Word Origin Middle English (as an adjective): from French, from Latin expertus, past participle of experiri
‘try’. The noun use dates from the early 19th cent. Compare with experience and experiment.Extra examples A panel of experts will answer questions from the television audience. Experts agree that a balanced diet is the key to great health. She is a world expert on butterflies. an expert in skin care an expert on European art I’m no expert, but I think you should get that cut seen to. Medical experts are predicting a massive rise in obesity-related illnesses. Professor Browne is a world-renowned expert on volcanic activity. She’s a leading expert in child psychology. The so-called experts seem to have no explanation for this. Weapons experts were sent to try to uncover evidence of a nuclear programme.