Answer
If the matrix does not have a multiplicative inverse, it is called "singular".
Work Step by Step
Consider the two matrices $A$ and $B$ to be the multiplicative inverses; that is, the product of the matrix $AB$ is equal to the identity matrix.
As example:
Let matrix $A=\left[ \begin{matrix}
4 & -3 \\
-5 & 4 \\
\end{matrix} \right]$ and $B=\left[ \begin{matrix}
4 & 3 \\
5 & 4 \\
\end{matrix} \right]$.
If $B$ is the multiplicative inverse of $A$, then $AB$ will result in the identity matrix ${{I}_{2}}=\left[ \begin{matrix}
1 & 0 \\
0 & 1 \\
\end{matrix} \right]$
And, if a square matrix does not have a multiplicative inverse, it is called singular.
