Co je alcohol? Co je alcohol? A colorless volatile flammable liquid, C2H5OH, synthesized or obtained by fermentation of sugars and starches and widely used, either pure or denatured, as a solvent and in drugs, cleaning solutions, explosives, and intoxicating beverages. Also called ethanol, ethyl alcohol, grain alcohol.Intoxicating liquor containing alcohol.Any of a series of hydroxyl compounds, the simplest of which are derived from saturated hydrocarbons, have the general formula CnH2n+1OH, and include ethanol and methanol.