expert
Word family
Synonym discussion
Sense: noun/1
An expert is someone with deep knowledge or skill gained through experience or training, and the term is widely used across all fields. A specialist focuses on a narrow, specific area — a heart specialist, for example, would not be called an expert in general medicine. An authority carries greater weight: their opinions are trusted and often decisive, like a leading authority on ancient Greek pottery. A professional is simply someone who does something for a living; many professionals are not experts (a newly qualified accountant is a professional but not yet an expert), and many experts are not professionals (an amateur astronomer can be an expert on comets). A master implies the highest level of practical skill, typically in crafts, music, or sports — a master carpenter or a chess master. In everyday use, expert is the safest choice: 'The gardener is an expert at growing roses.' For a narrower field, use specialist: 'She is a lung cancer specialist.' For weight and influence, use authority: 'He is the world authority on rare birds.'
Common collocations
Etymology
The word expert comes from the Latin expertus, meaning 'having been tried or tested,' the past participle of experiri, 'to try, test.' This root is also the source of experience and experiment. The word entered English through Old French in the 1300s, first as an adjective meaning 'experienced' and later as a noun meaning 'a person of experience.' The noun sense became more specialised over time, coming to mean someone whose experience gives them special knowledge in a particular area.