Im trying to hide a specific game object (as in not render it) unless I press a certain key.

So far I have this.

function Update(){

	var ShowObject = Input.GetAxis("ShowObject");

if(ShowObject=1)//"Show" key pressed
        /*Render Object, I don't know what to put here*/;

what code can I insert to make this work?

If the script is on the object you could so something like this:

if(showObject == 1)
{
   renderer.enabled = true
}
else
{
   renderer.enabled = false
}

btw, try and use camelCase for variables (start variables with a lowercase, keep capitals for Classes), it’s a common convention.