Underwater worker (7)
I believe the answer is:
frogman
'underwater worker' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for frogman that I've seen before include "Underwater swimmer with breathing apparatus" , "Swimmer working underwater" , "He searches lakes and rivers" , "Diver with breathing equipment" , "Rubber-suited diver" .)