Alcohol compatible, water-soluble copolymer useful as a corrosion inhibitor. The copolymer includes at least one olefinically unsaturated carboxylic acid monomer, at least one olefinically unsaturated mono- or di-alkyl ester of a di-carboxylic acid monomer, and at least one olefinically unsaturated hydrophilic, non-ionic monomer. The molar ratio of the alkyl ester groups of the mono- or di-alkyl ester of the dicarboxylic acid monomer to the hydrophilic groups of the hydrophilic, non-ionic monomers is from 0.0 1: to 1000:1, and the molar ratio of the sum of the alkyl ester groups and hydrophilic groups of the hydrophilic, non-ionic monomers to the carboxylic acid groups, is from 0.001:1 to 100:1. No haze or precipitate occurs in a mixture of the water-soluble copolymer at 4°C for 15 hrs or more as a 20 weight % aqueous copolymer solution in alcohol at a water-soluble copolymer to methanol weight-ratio of not more than 25 to 100.