Resting on a spinner (4)
I believe the answer is:
atop
'resting on' is the definition.
(I've seen this in another clue)
'a spinner' is the wordplay.
'spinner' becomes 'top' (a spinning top).
'a'+'top'='ATOP'
(Other definitions for atop that I've seen before include "Positioned on" , "On a high" , "on the head" , "Surmounting" , "highest level" .)