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 an anagram.
'ages' anagrammed gives 'SAGE'.
(Other definitions for sage that I've seen before include "Fragrant herb or wise man" , "Aromatic herb" , "Oracle; herb" , "Profoundly wise" , "Culinary herb" .)