What Is The Definition of "Perfect"?

Let the perfect fourth power be $x^4$ . We can rewrite it as $(x^2)^2$ . So it is also a perfect square.

It is easy to understand that for all positive integers $x$ , $x^4 = {(x^2)}^2$ . So it is always a perfect square.
For $x = 0$ , $0^4 = {(0^2)}^2$ so it is valid for $x = 0$ too.
Even for all negative integers $x$ , $x^4$ is positive and $x^2$ is positive too. So, $(x^2)^2$ is positive too and its magnitude is equal to $x^4$ . So, it is valid in this case too.

No need to check for decimals(non-integral) because they are not $\text{perfect}$ squares or fourth power.

So, the answer is $\color{#69047E}{\boxed{\text{True}}}$ .