A member of a historical reenactment organization who has appointed themselves the judge and jury over everyone elses historical clothing and, while sometimes correct in their assessment, makes everyone misarable because they are way too picky.
Also: nickname for a person in charge of maintaining authenticity at a historic site.
Person 1) I cant ware my moccasin boots anymore, I have to buy brogues!
Person 2) Why? they looked so good!
Person 1) Because that garb nazi made a fuss because the seams in the wrong place!