Explanation:
do you have any answer options ?
It is not clear what you mean by "description".
in any case, this limit expression means that the functional values (y values) get smaller and smaller (into the negative numbers) the larger x gets.
a typical example for f(x) would be
f(x) = -x
or simply
y = -x
which would be the diagonal line from the top left to the bottom right on the coordinate grid going through the origin (0, 0).