go through the mill

Meanings:

• 1.

  globalidiomatic
  • To undergo prolonged hardship, discipline, or testing that shapes one's skills, character, or mental state.

• 2.

  globalliteral
  • To be processed in a mill; to pass through machinery used for grinding, crushing, or similar operations.

• 3.

  UKslangobsolete
  • To become bankrupt or be declared insolvent (chiefly historical UK slang).