I have found a term which can be used to describe a person who knows a lot about a specific field. Imagine a carpenter or a mechanic or an electrician etc. who know a lot about their specialties and are very familiar with their own profession. How would one indicate such an ability in natural English?
This is what I found:
- He is very well versed in this / his business
I would relly appreciate it if someone could let me know whether there is a better term or idiom to explain such a person or not.