Definition of market man in US English:
market man
noun
1A man who buys or sells in a market.
2Stock Market. A person (especially a man) who works in a stock exchange.
Origin
Mid 16th century; earliest use found in Thomas Elyot (c1490–1546), humanist and diplomat. From market + man.
Pronunciation
market man
/ˈmɑːkɪt ˌman/