Herb wasted ages (4)
I believe the answer is:
sage
'herb' is the definition.
(sage is a kind of herb)
'wasted ages' is the wordplay.
'wasted' indicates anagramming the letters.
'ages' is an anagram of 'SAGE'.
(Other definitions for sage that I've seen before include "Fragrant herb or wise man" , "Aromatic herb" , "Oracle; herb" , "Profoundly wise" , "Culinary herb" .)