Timeless or eternal (7)
I believe the answer is:
ageless
I believe this clue is a double definition.
'timeless' is the first definition.
(synonyms)
'eternal' is the second definition.
(I know that eternal can be written as ageless)
(Other definitions for ageless that I've seen before include "Long-lasting -- sea legs (anag)" , "Classic" , "Enduring" , "Not growing older" , "Forever young" .)