  We present high-cadence ultraviolet (UV), optical, and near-infrared (NIR)
data on the luminous Type II-P supernova SN 2017gmr from hours after discovery
through the first 180 days. SN 2017gmr does not show signs of narrow,
high-ionization emission lines in the early optical spectra, yet the optical
lightcurve evolution suggests that an extra energy source from circumstellar
medium (CSM) interaction must be present for at least 2 days after explosion.
Modeling of the early lightcurve indicates a ~500R$_{\odot}$ progenitor radius,
consistent with a rather compact red supergiant, and late-time luminosities
indicate up to 0.130 $\pm$ 0.026 M$_{\odot}$ of $^{56}$Ni are present, if the
lightcurve is solely powered by radioactive decay, although the $^{56}$Ni mass
may be lower if CSM interaction contributes to the post-plateau luminosity.
Prominent multi-peaked emission lines of H$\alpha$ and [O I] emerge after day
154, as a result of either an asymmetric explosion or asymmetries in the CSM.
The lack of narrow lines within the first two days of explosion in the likely
presence of CSM interaction may be an example of close, dense, asymmetric CSM
that is quickly enveloped by the spherical supernova ejecta.
