  We report on high-statistics data from the $\beta^-$ decay of the $^{46}$K
$J^{\pi}$ = 2$^-$ ground state taken with the GRIFFIN spectrometer located at
the TRIUMF-ISAC facility. In total, 199 $\gamma$ rays and 42 excited states
were placed in the level scheme, and from the observed $\beta$ feeding and
angular correlations of pairs of cascading $\gamma$ rays, it was possible to
assign spins and parities to excited states and determine mixing ratios for
selected $\gamma$ rays. The level structure of $^{46}$Ca is compared to
theoretical predictions from a microscopic valence-space Hamiltonian derived
from two- (NN) and three-nucleon (3N) forces. These calculations are in
reasonable agreement with the experimental data and indicate that the protons
in this region are not as inert as would be expected for semi-magic nuclei.
