The refractive index of medium 2 with respect to medium 1 is greater than one. What does it imply?

If the refractive index of medium 2 with respect to medium 1 is greater than 1 it implies that the speed of light in medium 2 < speed of light in medium 1.

$n_{21 } > n_{12}$
$$\begin{gathered} \mathrm{Since}, \mathrm{n} = \frac{\mathrm{c}}{\mathrm{v}} \\ \mathrm{Similarly}, {\mathrm{n}}_{21 } =\frac{\mathrm{c}}{{\mathrm{v}}_{21}} \mathrm{and} {\mathrm{n}}_{12 } =\frac{\mathrm{c}}{{\mathrm{v}}_{12}} \end{gathered}$$

As, 'n' is inversely proportional to 'v', and  $n_{21} > n_{12}$. Hence,  $v_{12} > v_{21}$