  The observation of a compact object with a mass of $2.50-2.67M_{\odot}$ on
August 14, 2019, by the LIGO Scientific and Virgo collaborations (LVC) has the
potential to improve our understanding of the supranuclear equation of state.
While the gravitational-wave analysis of the LVC suggests that GW190814 likely
was a binary black hole system, the secondary component could also have been
the heaviest neutron star observed to date. We use our previously derived
nuclear-physics-multimessenger astrophysics framework to address the nature of
this object. Based on our findings, we determine GW190814 to be a binary black
hole merger with a probability of $>99.9\%$. Even if we weaken previously
employed constraints on the maximum mass of neutron stars, the probability of a
binary black hole origin is still $\sim 81\%$. Furthermore, we study the impact
that this observation has on our understanding of the nuclear equation of state
by analyzing the allowed region in the mass-radius diagram of neutron stars for
both a binary black hole or neutron star--black hole scenario. We find that the
unlikely scenario in which the secondary object was a neutron star requires
rather stiff equations of state with a maximum speed of sound $c_s\geq
\sqrt{0.6}$ times the speed of light, while the binary black hole scenario does
not offer any new insight.
