(57) The present invention provides for a thickener composition characterized by: (1) at least one water-soluble, thermoplastic, organic polymer having a weight average molecular weight of at least about 10,000 which comprises hydrophobic segments, each containing at least one monovalent hydrophobic group covalently bonded to the polymer, wherein the polymer has an amount of hydrophobe bunching comprising at least two monovalent hydrophobic groups per hydrophobic segment, sufficient to provide for enhanced thickening of aqueous solutions containing the polymer, and (2) at least one ethoxylated alcohol selected from the group consisting of C₉-C₁₅ saturated alcohols with between about 5 and 20 moles of ethylene oxide per mole of alcohol and having an HLB between 11 and 14, and C^g-Ci₈ unsaturated alcohols with between about 5 and 20 moles of ethylene oxide per mole of alcohol and having an HLB between 11 and 14. Said thickener compositions as well as hydraulic fluid and metalworking fluid concentrates, aqueous concentrates and water-based hydraulic fluid and metalworking fluid or lubricant compositions are thickened to an oil-like viscosity by said low solids combination of thickeners.