  In this paper, we present a characterization of support functionals and
smooth points in $L_{0}^{\Phi}$, the Musielak-Orlicz space equipped with the
Orlicz norm. As a result, criterion for the smoothness of $L_{0}^{\Phi}$ is
also obtained. Some expressions involving the norms of functionals in
$(L_{0}^{\Phi})^{*}$, the topological dual of $L_{0}^{\Phi}$, are proved for
arbitrary Musielak-Orlicz functions.
