  We present the discovery of a charge density wave (CDW) ground state in
heavily electron-doped molybdenum disulfide (MoS$_2$). This is the first
observation of a CDW in any $d^2$ (column 6) transition metal dichalcogenide
(TMD). The band structure of MoS$_2$ is distinct from the $d^0$ and $d^1$ TMDs
in which CDWs have been previously observed, facilitating new insight into CDW
formation. We demonstrate a metal-insulator transition at 85 K, a 25 meV gap at
the Fermi level, and two distinct CDW modulations,
$(2\sqrt{3}\times2\sqrt{3})$R$30^\circ$ and $2\times2$, attributable to Fermi
surface nesting (FSN) and electron-phonon coupling (EPC), respectively. This
simultaneous exhibition of FSN and EPC CDW modulations is unique among
observations of CDW ground states, and we discuss this in the context of band
folding. Our observations provide a route toward the resolution of
controversies surrounding the origin of CDW modulations in TMDs.
