Final answer:
The term to describe hyperpigmentation caused by overactivity of melanocytes is hyperpigmentation, where excess melanin results in darker skin patches.
Step-by-step explanation:
The term used to describe any hyperpigmentation caused by overactivity of the melanocytes in the epidermis is called hyperpigmentation. Hyperpigmentation is a condition where the melanocytes produce more melanin than usual, resulting in darker patches of skin. This is in contrast to conditions like albinism, which is characterized by a complete or partial lack of melanin production leading to very pale skin, and vitiligo, which involves a loss of melanin in certain patches of the skin, often due to an autoimmune reaction. Conversely, melanoma is a type of skin cancer that arises from melanocytes, but it's not related to the overproduction of melanin for pigmentation purposes.