Loosening or detachment of the nails from the nail bed is known as:

Correct option is D

Onycholysis is the medical term for the loosening or detachment of the nail from the nail bed. It can be caused by various factors, including trauma, fungal infections, or underlying medical conditions.
Explanation of options: (a) ✘ Incorrect. Onychomycosis is a fungal infection of the nails. (b) ✘ Incorrect. Koilonychia refers to spoon-shaped nails, often associated with iron deficiency anemia. (c) ✘ Incorrect. Paronychia is an infection of the skin around the nail. (d) ✔ Correct. Onycholysis specifically refers to the detachment of the nail from the nail bed.