  In this paper we are concerned with some abstract results regarding to
fractional Orlicz-Sobolev spaces. Precisely, we ensure the compactness
embedding for the weighted fractional Orlicz-Sobolev space into the Orlicz
spaces, provided the weight is unbounded. We also obtain a version of Lions'
"vanishing" Lemma for fractional Orlicz-Sobolev spaces, by introducing new
techniques to overcome the lack of a suitable interpolation law. Finally, as a
product of the abstract results, we use a minimization method over the Nehari
manifold to prove the existence of ground state solutions for a class of
nonlinear Schr\"{o}dinger equations, taking into account unbounded or bounded
potentials.
