Turning back, eased naturally outside range (5)
I believe the answer is:
andes
'range' is the definition.
(Andes is an example)
'turning back eased naturally outside' is the wordplay.
'turning back' says the letters should be written backwards.
'outside' says the answer is hidden in the clue (a word is around or outside the answer).
'sedna' can be found hidden inside 'eased naturally'.
'sedna' written backwards gives 'ANDES'.
(Other definitions for andes that I've seen before include "danes found in mountains" , "South American mountain system" , "Danes in S American mountains" , "Great mountains of western S America" , "Mountains in west" .)