The invention relates to a copolymer obtained by polymerisation reaction of at least three comonomers: a first anionic monomer, a second monomer comprising an olefin unsaturation, and a third monomer comprising a hydrophobic group. The invention likewise relates to the use of said copolymer as a thickening agent, in particular in aqueous suspensions of mineral particles with high solids content. The copolymer according to the invention makes it possible to improve the compromise between viscosity with high shear gradient and viscosity with low shear gradient, while also improving water retention inside the suspension.