  The compound V$_5$S$_8$ can also be represented by V$_{1.25}$S$_2$, a
transition metal dichalcogenide (TMDC) with excess V. Very few TMDCs show
magnetism and/or Kondo effect. Among them, the sister compounds VSe$_2$ and
VTe$_2$ are recently proved to show ferromagnetism in addition to the
low-temperature resistivity upturn due to Kondo effect. In this study, we show
Kondo effect in V$_5$S$_8$ originated from the antiferromagnetic exchange
interactions among the intercalated V atoms below the N$\acute{e}$el ($T_N$)
temperature of 27 K. We find isotropic magnetic properties above $T_N$, while a
strong magnetic anisotropy is noticed below $T_N$. In addition, below $T_N$ we
find an out-of-plane ($H\parallel c$) spin-flop transition triggered at a
critical field of 3.5 T that is absent from the in-plane ($H\perp c$).
Angle-dependent magnetoresistance is found to be highly anisotropic in the
antiferromagnetic state.
