diver; underwater worker
Refers to a person who works underwater, typically in a professional or industrial context such as construction, inspection, or salvage.
The diver inspected the bridge pier.
ダイバー is a more general term for a diver, including recreational scuba divers, while 潜水作業員 specifically implies a professional underwater worker.
Compound of 潜水 (diving, underwater) + 作業 (work, operation) + 員 (person, member).