Final answer:
The strong nuclear force is the adjective used to describe the force that overcomes electromagnetic repulsion to hold protons together in an atomic nucleus.
Step-by-step explanation:
The adjective used to describe the force holding protons together in the nucleus is strong. The strong nuclear force is a very powerful force that acts over short distances (about 10-15 meters), and is responsible for binding protons and neutrons together in atomic nuclei. Despite the repulsive electromagnetic forces causing positively charged protons to push away from each other, the strong nuclear force is strong enough to overcome this repulsion and hold the nucleus together.