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' is a reversal indicator.
'tops' reversed gives 'SPOT'.
(Other definitions for spot that I've seen before include "See 5" , "small amount" , "Notice - place" , "Discern - mark" , "Observe - place" .)