an oily, acrid, poisonous liquid occurring in imperfectly distilled alcoholic products and consisting chiefly of amyl alcohols: small amounts contribute to the characteristic flavor of a whiskey
Origin:
Ger fusel, inferior liquor < L fusilis, fusil
See fusel oil in American Heritage Dictionary 4
noun
An acrid, oily, poisonous liquid mixture of amyl alcohols, occurring in incompletely distilled alcoholic liquids and used as a solvent and in the manufacture of explosives and pure amyl alcohols.