Cats and dogs etc, son held, can be pains (5)
I believe the answer is:
pests
'be pains' is the definition.
(I've seen this in another clue)
'cats and dogs etc son held' is the wordplay.
I cannot really see how this works, but
'son' could be 's' (genealogical abbreviation for son) and 's' is found within the answer.
'dogs etc' could be 'pets' and 'pets' is present in the leftover letters.
This accounts for all the letters.
This may be the basis of the clue (or it may be nonsense).
'can' acts as a link.
Can you help me to learn more?
(Other definitions for pests that I've seen before include "Steps (anag.)" , "Steps taken about nuisances" , "Persistently annoying persons" , "Take steps to troublesome animal." .)