In retrospect, some artists always endure (4)
I believe the answer is:
last
'endure' is the definition.
(I know that endure is a more specific form of endure)
'in retrospect some artists always' is the wordplay.
'in retrospect' says the letters should be written in reverse (in retrospect means looking back).
'some' indicates a hidden word (some parts of the word are used).
'tsal' can be found hidden inside 'artists always'.
'tsal' backwards is 'LAST'.
(Other definitions for last that I've seen before include "part of Oxford's restoration with this?" , "Final; keep going" , "Shoemaker's shape" , "End" , "Endure - this clue is!" .)