  Despite the large baryon-anti-baryon asymmetry in the observed Universe, the
closely related phenomenon -- the violation of the combined charge and parity
symmetry ($C\!P$V) -- has not been observed in the baryon sector in
laboratories. With more and more data available in collaborations such as LHCb,
$C\!P$V is now able to be investigated through multi-body decays of heavy
hadrons such as $B$ meson, $D$ meson, bottom and charmed baryons. In this
paper, a new strategy for searching for $C\!P$V in this kind of decays is
proposed, in which, a set of novel observables measuring $C\!P$V in multi-body
decays of heavy hadrons -- the partial wave $C\!P$ asymmetries (PW$C\!P$As) --
are introduced. This strategy is model-independent and applicable to multi-body
decays of heavy hadrons with arbitrary spin configurations in both initial and
final states, and with any number of particles in the final state, which is
larger than 2. The introduction of PW$C\!P$As provides a systematic way to
investigate the underling mechanism corresponding to $C\!P$V in multi-body
decays of bottom and charmed hadrons. Especially, it can be used in searching
for $C\!P$V in the baryon sector. We propose to search for $CP$V in multi-body
decays of heavy baryons such as $\Lambda_b^0\to p \pi^+\pi^-\pi^+$, through the
measurement of the PW$C\!P$As. Hopefully, $C\!P$V in the baryon sector could be
first discovered through the measurement of the PW$C\!P$As in some multi-body
decay channels of bottom or charmed baryons.
