The very best place for retirement (4)
I believe the answer is:
tops
'the very best' is the definition.
(I've seen this in another clue)
'place for retirement' is the wordplay.
'place' becomes 'spot' (synonyms).
'for retirement' says the letters should be written backwards (retire can mean to retreat or go backwards).
'spot' reversed gives 'TOPS'.
(Other definitions for tops that I've seen before include "First-class" , "spinners" , "The Four -, Motown group" , "Upper garments" , "The best" .)