Pair of seals when swimming? Group not round seal at sea (8)
I believe the answer is:
earplugs
'pair of seals when swimming?' is the definition.
(earplugs might seal a swimmer's ears up)
'group not round seal at sea' is the wordplay.
I cannot quite understand how this works, but
'seal' could be 'plug' (I've seen this before) and 'plug' is found in the answer.
The remaining letters 'ears' is a valid word which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for earplugs that I've seen before include "aids to sleep?" , "Stoppers to keep noise out" , "noise abatement aids" .)