Measurements of $C!P$ observables in $B^pm rightarrow D^{(*)} K^pm$ and $B^pm rightarrow D^{(*)} pi^pm$ decays are presented, where $D^{(*)}$ indicates a neutral $D$ or $D^*$ meson that is an admixture of meson and anti-meson states. Decays of the $D^*$ meson to the $Dpi^0$ and $Dgamma$ final states are partially reconstructed without inclusion of the neutral pion or photon. Decays of the $D$ meson are reconstructed in the $K^pm pi^mp$, $K^+K^-$, and $pi^+pi^-$ final states. The analysis uses a sample of charged $B$ mesons produced in proton-proton collisions and collected with the LHCb experiment, corresponding to integrated luminosities of 2.0, 1.0, and 5.7 fb$^{-1}$ taken at centre-of-mass energies of 7, 8, and 13 TeV, respectively. The measurements of partially reconstructed $B^pm to D^* K^pm$ and $B^pm to D^* pi^pm$ with $D to K^mp pi^pm$ decays are the first of their kind, and a first observation of the $B^pm to (D pi^0)_{D^*} pi^pm$ decay is made with a significance of 6.1 standard deviations. All $C!P$ observables are measured with world-best precision, and in combination with other LHCb results will provide strong constraints on the CKM angle $gamma$.
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