  We analyze the very short Einstein timescale ($t_\rm E \simeq 7\,{\rm hr}$)
event KMT-2019-BLG-2073. Making use of the pronounced finite-source effects
generated by the clump-giant source, we measure the Einstein radius $\theta_\rm
E \simeq 4.8\,\rm \mu as$, and so infer a mass $M = 59\,M_\oplus
(\pi_\rm{rel}/16 \,\rm \mu as)^{-1}$, where $\pi_\rm{rel}$ is the lens-source
relative parallax. We find no significant evidence for a host of this planetary
mass object, though one could be present at sufficiently wide separation. If
so, it would be detectable after about 10 years. This is the fourth isolated
microlens with a measured Einstein radius $\theta_\rm{E}<10\,\rm \mu as$, which
we argue is a useful threshold for a "likely free-floating planet (FFP)"
candidate. We outline a new approach to constructing a homogeneous sample of
giant-star finite-source/point-lens (FSPL) events, within which the subsample
of FFP candidates can be statistically analyzed. We illustrate this approach
using 2019 KMTNet data and show that there is a large $\theta_\rm{E}$ gap
between the two FFP candidates and the 11 other FSPL events. We argue that such
sharp features are more identifiable in a sample selected on $\theta_\rm{E}$
compared to the traditional approach of identifying candidates based on short
$t_\rm{E}$.

Earth and Planetary Astrophysics;Astrophysics of Galaxies;Instrumentation and Methods for Astrophysics;Solar and Stellar Astrophysics