The Collaborative International Dictionary of English v.0.48:
rotgut \rot"gut\, n. 1. Bad small beer. [Slang] [1913 Webster] 2. Any bad spirituous liquor, especially when adulterated so as to be very deleterious. [Slang] [1913 Webster]WordNet (r) 3.0 (2006):
rotgut n 1: any alcoholic beverage of inferior quality