A slouch hat is a wide-brimmed felt or cloth Hat most commonly worn as part of a Military Uniform, mainly Australian, New Zealander or Rhodesian militaries. It is not always worn with a Chinstrap and the brim may be bent up. While it resembles the Cowboy Hat, usage context is for military-themed outfits and settings.
Not to be confused with the Boonie Hat which appears to be lighter and softer.