1. What does it mean when gravity is called an "attractive force"?

It means that gravity is a force of attraction between objects. Weight is a measure of the gravitational force on an object. When you see or hear the word weight, it usually refers to Earth's gravitational force on an object. But weight can also be a measure of the gravitational force exerted on objects by the moon or other planets.

It means that the forces of gravity always act in the direction to pull masses together, never to push them apart. Gravity always 'attracts'.