See tops spinning (4)
I believe the answer is:
spot
'see' is the definition.
(to spot is to notice or catch sight of)
'tops spinning' is the wordplay.
'spinning' shows that the letters should be reversed in order.
'tops' written backwards gives 'SPOT'.
(Other definitions for spot that I've seen before include "See 5" , "small amount" , "Notice - place" , "Discern - mark" , "Observe - place" .)