  Recently, unconventional antiferromagnets that enable the splitting of
electronic spins have been theoretically proposed and experimentally realized,
where the magnetic sublattices containing moments pointing at different
directions are connected by a novel set of symmetries. Such spin splitting (SS)
is substantial, $k$-dependent, and independent of the spin-orbit coupling
strength, making these magnets promising materials for antiferromagnetic
spintronics. Here, combined with angle-resolved photoemission spectroscopy
(ARPES) and density functional theory (DFT) calculations, we perform a
systematic study on CrSb, a metallic spin-split antiferromagnet candidate with
$T_N$ = 703 K. Our data reveals the electronic structure of CrSb along both
out-of-plane and in-plane momentum directions, which renders anisotropic
$k$-dependent SS and agrees well with the calculational results. The magnitude
of such SS reaches up to at least 0.8 eV at non-high-symmetry momentum points,
which is significantly higher than the largest known SOC-induced SS. This
compound expands the choice of materials in the field of antiferromagnetic
spintronics and is likely to stimulate subsequent investigations of
high-efficiency spintronic devices that are functional at room temperature.
