Planet while revolving with revolution (6)
I believe the answer is:
'planet' is the definition.
(Saturn is an example)
'while revolving with revolution' is the wordplay.
'while' becomes 'as'.
'revolving' shows that the letters should be reversed in order.
'with' says to put letters next to each other.
'revolution' becomes 'turn' (I've seen this before).
'as' back-to-front is 'sa'.
(Other definitions for saturn that I've seen before include "One of the 1 across" , "Solar system planet" , "Nearest ringed planet" , "space traveller" , "Titan its moon" .)