Various frogmen (6)
I believe the answer is:
divers
I believe this clue is a double definition.
'various' is the first definition.
(I've seen this before)
'frogmen' is the second definition.
('diver' can be a synonym of 'frogman')
(Other definitions for divers that I've seen before include "Various; frogmen" , "Penguins, say" , "varying types from the past" , "footballers going to the ground, needlessly" , "Some water-birds; assorted" .)