What is the meaning of Inverse_function?

For a given function f, another function, denoted f, that reverses the mapping action of f; given a function ${\displaystyle f:X\rightarrow Y}$, a function ${\displaystyle g:Y\rightarrow X}$ such that, ${\displaystyle \forall x\in X,\ f(x)=y\implies g(y)=x}$.

Source: wiktionary.org