Definition of dry rot:
		
		
		(n) :
		
		the crumbly, friable decayed portions of wooden members of buildings, especially at or below grade, usually caused by a fungal infection; metaphorically, a progressive malaise of decay, corruption, or datedness
		
								
				"1952 Therefore I am like a moth to Ephraim, and like dry rot to the house of Judah. Hosea 5:12, 
RSV"