Folder about elderly (3)
I believe the answer is:
old
'elderly' is the definition.
(similar in meaning)
'folder about' is the wordplay.
'about' indicates a hidden word (the clue goes around or about the answer).
'OLD' is hidden within 'folder'.
(Other definitions for old that I've seen before include "Wild clematis" , "Elderly" , "Obsolete" , "Vintage" , "Ancient" .)