Which tool is primarily used for shaping and smoothing nails?

The tool primarily used for shaping and smoothing nails is the nail file. Nail files have a rough surface that helps refine the edge of the nails, allowing for various shapes such as square, oval, or almond to be achieved. They are essential in the nail care process as they remove any jagged edges and create a smooth finish, helping to prevent breakage and ensuring the polish applies evenly and lasts longer.

The nail clip is used primarily for cutting nails, which is a different function compared to shaping and smoothing. The cuticle pusher is designed to push back the cuticles rather than alter the shape or finish of the nail itself. The buffer, while used for smoothing the nail surface and giving it shine, does not provide the shaping function that the nail file offers. Therefore, the nail file is the most appropriate choice for shaping and smoothing nails.