As $x\to+\infty$, $-\frac1x$ approaches $0$ from the negative side; it is negative for any sufficiently large finite $x$. Thus we must conclude that the limit of its floor is $-1$, this being the floor of an arbitrarily small (in magnitude) negative number.
As $x\to+\infty$, $-\frac1x$ approaches $0$ from the negative side; it is negative for any sufficiently large finite $x$. Thus we must conclude that the limit of its floor is $-1$, this being the floor of an arbitrarily small (in magnitude) negative number.