How can you say that gravitational force is a field force?
The force of gravity can indeed be described as a force field. Any object having mass will create a gravitational attraction in all directions, with decreasing intensity as the distance from the object increases.
The weight of a body is due to the gravitational force with which the Earth attracts a body. Gravitational force is a non-contact force.
For example, the velocity of a body, thrown up, goes on decreasing while on return its velocity goes on increasing. This is due to the gravitational pull of the Earth acting on the body whether the body is in contact with the Earth or not. Such a force is called the field force. It is assumed that a gravitational field exists all around the Earth.