{adv. phr.} 1. Experienced. * /You could tell immediately that the new employee had been through the mill./ 2. Through real experience of the difficulties of a certain way of life. * /Poor Jerry has had three operations in one year, and now he's back in the hospital. He's realty gone through the mill./ Compare: GO THROUGH HELL AND HIGH WATER, COME HELL OR HIGH WATER.
THROUGH THE MILL
Meaning of THROUGH THE MILL in English
Dictionary of English idioms . Словарь английских идиом. 2012