scuba diver
['breakwater, groin, groyne, mole, bulwark, seawall, jetty', 'lawn mower, mower', 'barracouta, snoek', 'binder, ring-binder', 'great white shark, white shark, man-eater, man-eating shark, Carcharodon carcharias', 'oscilloscope, scope, cathode-ray oscilloscope, CRO', 'loudspeaker, speaker, speaker unit, loudspeaker system, speaker system']