1) Acrid oily liquid 2) Fermentation oil 
• Alt. of Fusel oil
Fu'sel noun , Fu'sel oil [ German fusel bad liquor.] (Chemistry) A hot, acrid, oily liquid, accompanying many alcoholic liquors (as potato whisky, corn whisky, etc.), as an undesirable ingredient, and consisting of several of the higher alcohols and compound ethers, but particularly o...