Some crocodiles over in pool (4)
I believe the answer is:
lido
'pool' is the definition.
(I've seen this before)
'some crocodiles over in' is the wordplay.
'in' indicates the answer is hidden within the clue.
'over' says the letters should be written in reverse.
'odil' is hidden in the letters of 'some crocodiles'.
'odil' reversed gives 'LIDO'.
(Other definitions for lido that I've seen before include "Bathing pool" , "Outdoor swimming pool" , "Idol (anag.)" , "bathing facilities" , "Italian bathing place" .)