Moonshine (sometimes known as PoitÃn, mooney, moonshizzle, mountain dew, moon, branch or creek water, hooch, squeezings, rot gut, gut rot, corn liquor, Portuguese grape juice, white lightning, and many others) is a common slang term for home-distilled alcohol, or whiskey for the hills, especially in places where this production is illegal.
The name is often assumed to be derived from the fact that moonshine producers and smugglers would often work at night (i.e. under the light of the moon) to avoid arrest for producing illegal liquor. The 1811 edition of the Dictionary of the Vulgar Tongue, originally by Francis Grose, defines "moonshine" as follows: "A matter or mouthful of moonshine; a trifle, nothing. The white brandy smuggled on the coasts of Kent and Sussex, and the gin in the north of Yorkshire, are also called moonshine." It has been suggested that the term might derive from smugglers' explaining away their boxes and barrels as "mere moonshine" (that is, nothing). (Jonathon Green, American Dialect Society Mailing List, 31 Oct 2001)
Moonshine is made by yeast fermenting a sugar source to produce ethanol and then separating the alcohol from the fermenting mixture (the mash) through distillation using a still. Because of its illegal nature in many states and simple production, moonshine is usually not aged in barrels as are other, similarly-produced liquors such as whisky or bourbon, and it sometimes contains impurities, off flavors, and toxins such as methanol that the more sophisticated distillation methods of commercial distilleries are able to control. In popular culture, moonshine is usually presented as being extremely strong and in North America is commonly associated with the Southern United States, and Appalachia.