[en] Here, at the Fermilab Tevatron proton-antiproton (pp̄) collider, Drell-Yan lepton pairs are produced in the process pp̄→e"+e"-+X through an intermediate γ*/Z boson. The forward-backward asymmetry in the polar-angle distribution of the e"- as a function of the e"+e"--pair mass is used to obtain sin"2θ((lept)/(eff)), the effective leptonic determination of the electroweak-mixing parameter sin2θW. The measurement sample, recorded by the Collider Detector at Fermilab (CDF), corresponds to 9.4 fb"-"1 of integrated luminosity from pp̄ collisions at a center-of-momentum energy of 1.96 TeV, and is the full CDF Run II data set. The value of sin"2θ((lept)/(eff)) is found to be 0.23248±0.00053. The combination with the previous CDF measurement based on μ"+μ"- pairs yields sin"2θ((lept)/(eff))=0.23221±0.00046. This result, when interpreted within the specified context of the standard model assuming sin"2θW=1-M(2/W)/M(2/Z) and that the W- and Z-boson masses are on-shell, yields sin"2θW=0.22400±0.00045, or equivalently a W-boson mass of 80.328±0.024 GeV/c"2.