Grog -- from a coarse fabric worn by an admiral

from wordsmith.org

grog (grog) noun
1. An alcoholic drink, especially rum diluted with water.
2. Any strong alcoholic drink.

[After Old Grog, nickname of Admiral Edward Vernon (1684-1757), who ordered diluted rum to be served to his sailors. The admiral earned the nickname from his habit of wearing a grogram cloak. Grogram is a coarse fabric of silk, wool, mohair, or a blend of them. The word grogram is from French gros grain (large grain or texture).]

"Knowing the value of terse composition and wordplay, Mr. Paisley scored a country hit a couple of years ago with 'Alcohol': A droll defense of grog from the drink's point of view ('I've been known to cause a few breakups/And I've been known to cause a few births.')"

--Movies, Performing Arts; The New York Times; Jul 27, 2007.