Sundry people who take the plunge (6)
I believe the answer is:
divers
This might be a double definition.
'sundry' is the first definition.
(I've seen this in another clue)
'people who take the plunge' is the second definition.
'divers' can be an answer for 'people' (diver is a kind of person). I'm not certain of the rest of the definition.
Can you help me to learn more?
(Other definitions for divers that I've seen before include "Several; snorkellers" , "ducks" , "Way back, various" , "footballers going to the ground, needlessly" , "footballers cheating" .)