Idiot swallowing Sun's spin (5)
I believe the answer is:
twist
'spin' is the definition.
('twist' can be a synonym of 'spin')
'idiot swallowing sun's' is the wordplay.
'idiot' becomes 'twit' (I've seen this in other clues).
'swallowing' indicates putting letters inside.
'sun' becomes 's'.
'twit' placed around 's' is 'TWIST'.
(Other definitions for twist that I've seen before include "racket" , "Writhe" , "Energetic dance for twits" , "See 16" , "Embellishment to plot" .)