It's any-branch-of-the-military wife -- and husband sometimes -- who sits around getting fat.  There were only a handful of Army wives when I was in who were fit; the vast herd of them were all fat and nasty, slutting around on their spouses, etc.  But that might have been especially bad because I was stationed at Fort Drum: http://www.urbandictionary.com/define.php?term=Fort%20Drum