  We present measurements of the forward-backward asymmetry in the angular
distribution of leptons from decays of top quarks and antiquarks produced in
proton-antiproton collisions. We consider the final state containing a lepton
and at least three jets. The entire sample of data collected by the D0
experiment during Run II of the Fermilab Tevatron Collider, corresponding to
9.7 inverse fb of integrated luminosity, is used. The asymmetry measured for
reconstructed leptons is $A_{FB}^l = \big(2.9 \pm 2.1(stat.)
^{+1.5}_{-1.7}(syst.) \big)$%. When corrected for efficiency and resolution
effects within the lepton rapidity coverage of $|y_l|<1.5$, the asymmetry is
found to be $A_{FB}^l = \big(4.2 \pm 2.3(stat.) ^{+1.7}_{-2.0}(syst.) \big)$%.
Combination with the asymmetry measured in the dilepton final state yields
$A_{FB}^l = \big(4.2 \pm 2.0(stat.) \pm 1.4(syst.) \big)$%. We examine the
dependence of $A_{FB}^l$ on the transverse momentum and rapidity of the lepton.
The results are in agreement with predictions from the next-to-leading-order
QCD generator \mcatnlo, which predicts an asymmetry of $A_{FB}^l = 2.0$% for
$|y_l|<1.5$.
