|1.||a shirt made of haircloth worn next to the skin as a penance|
|2.||a secret trouble or affliction|
A self-imposed punishment or penance, as in I apologized a dozen timesdo you want me to wear a hair shirt forever? This term, mentioned from the 13th century on, alludes to wearing a coarse, scratchy hair shirt, the practice of religious ascetics. Its figurative use dates from the mid-1800s.