  The coexistence of seemingly mutually exclusive properties such as
ferromagnetism, ferroelectricity and metallicity in atomically thin materials
is the requirement of the hour in electronics as the Moore's law faces an
impending end. Only a few 2D multiferroic materials have been
predicted/realized so far. The polar metals with simultaneous presence of
polarity and conductivity are also equally rare. Here, we predict, based on
first-principles calculations that an Eu-substituted rare-earth halide GdI$_2$
monolayer showcases ferromagnetism, ferroelasticity while being polar and a
fully spin-polarized semi-metal at the same time. The ferroelasticity and
polarity are shown to be coupled making it possible to switch the polar
direction using external mechanical stress. Further, it is observed that, an
application of biaxial tensile strain of $5\%$ causes the spin easy-axis to
shift from out-of-plane to in-plane direction. Thus spin easy axis gets coupled
with the direction of polarization in the strained monolayer making the
switching of magnetization also possible using external strain. Simultaneous
coexistence and coupling of the ferroic orders in a metallic 2D material makes
the Eu substituted GdI$_2$ monolayer an incredibly rare material for
nano-electronics and spintronics applications.
