Small pool (4)
'small pool' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for puddle that I've seen before include "Small amount of standing water" , "Small amount of standing rainwater" , "A small pool as of rain" , "Small pool of muddy water" , "Small pool of rainwater" .)
(Another definition for hottub that I've seen is " outdoor jacuzzi".)
(Other definitions for pond that I've seen before include "Possible site for weed" , "Small area of still water" , "Himalayan country" , "Small lake" , "Small body of water" .)