Sentence:  Not only were the soldiers not allowed to tell anyone what was happening, but they had to remove their shoulder patches and the airborne patches from their hats, take off their jump wings, and <WSD>unblouse</WSD> their trousers to hide their jump boots. 
Meaning of the word marked with <WSD> tags:  To untuck (leggings from footwear); to make (pants or trousers) unrestricted or untightened at the ankle, often as a sign of rank or service.