Mechanic and master at work (9)

I believe the answer is:
tradesman
'mechanic' is the definition.
The definition and answer can be both people as well as being singular nouns.
Perhaps there's an association between them I don't understand?
'and master at work' is the wordplay.
'at work' indicates an anagram.
'and'+'master'='andmaster'
'andmaster' with letters rearranged gives 'TRADESMAN'.
Can you help me to learn more?
(Other definitions for tradesman that I've seen before include "Retailer - artisan" , "One buying and selling" , "Shopkeeper; skilled mechanic" , "Small businessman" , "A skilled worker like plasterer or joiner" .)
