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